Sometimes, the introduction of a Sequence, or the figure called Rosalia, affords opportunities for very effective treatment.
![{ \relative b' { \key e \minor \time 4/4
r8 b c e, dis ais' b d, | cis gis' a c, b g' fis e |
dis c' b a g8.[ fis16 e8] } }](http://upload.wikimedia.org/score/n/7/n7cavak3wn3a8suq145we1dsrvcli1z/n7cavak3.png)
Sebastian Bach constantly made use of this device in his Pedal Fugues, the Subjects of which are among the longest on record. There are few Subjects in which this peculiarity is carried to greater excess than in that of his Pedal-Fugue in E Major.
Very different from these are the Subjects designed by learned Contrapuntists for the express purpose of complicated devices. These are short, massive, characterised by extremely concordant Intervals, and built upon a very simple rhythmic foundation. Two fine examples are to be found in Bach's 'Art of Fugue'; and the 'Et vitam' of Cherubini's 'Credo' in G for 8 voices.
Next in importance to the Subject is the Answer; which, indeed, is neither more nor less than the Subject itself, presented from a different point of view. We have already said that the Tonal Answer must accommodate itself, not to the Intervals of the Subject, but, to the organic constitution of the Scale. The essence of this accommodation consists in answering the Tonic by the Dominant, and the Dominant by the Tonic: not in every unimportant member of the Subject—for this would neither be possible nor desirable—but in its more prominent divisions. The first thing is to ascertain the exact place at which the change from Real to Tonal Imitation must be introduced. For this process there are certain laws. The most important are—
(1) When the Tonic appears in a prominent position in the Subject, it must be answered by the Dominant; all prominent exhibitions of the Dominant being answered in like manner by the Tonic. The most prominent positions possible are those in which the Tonic passes directly to the Dominant, or the Dominant to the Tonic, without the interpolation of any other note between the two; and, in these cases, the rule is absolute.
(2) When the Tonic and Dominant appear in less prominent positions, the extent to which Rule 1 can be observed must be decided by the Composer's musical instinct. Beginners, who have not yet acquired this faculty, must carefully observe the places in which the Tonic and Dominant occur; and, in approaching or quitting those notes, must treat them as fixed points to which it is indispensable that the general contour of the passage should accommodate itself.
(a) Dominant, answered by Tonic, at (c).
(b) Dominant, answered by Supertonlc, at (d).
(3) The observance of Rules 1 and 2 will ensure compliance with the next, which ordains that all passages formed on a Tonic Harmony, in the Subject, shall be formed upon a Dominant Harmony in the Answer, and vice versâ.
(4) The Third, Fourth, and Sixth of the Scale should be answered by the Third, Fourth, and Sixth of the Dominant, respectively.
(a) Sixth of Tonic. (b) Third of Tonic. (c) Fourth of Tonic.
(d) Sixth of Dominant (e) Third of Dominant.
(f) Fourth of Dominant.
(5) The Interval of the Diminished Seventh, whether ascending or descending, should be answered by a Diminished Seventh.
(6) As a general rule, all Sevenths should be answered by Sevenths; but a Minor Seventh, ascending from the Dominant, is frequently answered by an ascending Octave; in which case, its subsequent descent will ensure conformity with Rule 4, by making the Third of the Dominant answer the Third of the Tonic.
