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Two-Part Counterpoint
Second Order: Two Notes Against One
Rule 9
In this order of counterpoint, two minims 1) should be placed over every semibreve 2) of the cantus firmus, except for the last bar, where a semibreve 3) should always be put against a semibreve 4).
The first part of the bar which is occupied by a minim 5), is called the accented part of the bar; and the second part occupied equally by another minim 6), is called the unaccented part of the bar.
Rule 10
The accented part of the bar should be in concord 7); although there are cases, where this may allow for variation, – that is to say, by employing a discord 8) at the accented part of the bar; but this can only be in certain dilemmas, either that the melody shall not be too disjunct, or to avoid other objectionable points.
The unaccented part of the bar may consist of a concord 9), or else of a discord 10), provided this latter be introduced between two concords 11), and that the movement of the melody be conjunct. In such a case, this discord 12) is called a passing tone.
Rule 11
The accented parts of the bar are not in this order subjected to Rule 4; provided, however, that the infraction of that rule be corrected in the unaccented part, – by which is meant: Firstly, that the unaccented parts shall strike another concord 13). Secondly, that from the accented part of the bar to the unaccented, the procedure shall be by an interval of more than a third. Thirdly, that in proceeding from the accented to the unaccented part, it shall be by contrary movement.
Demonstrations – It shall now be seen, whether, in fulfilling the prescribed conditions, several consecutive 14) fifths might be saved.
Fault (parallel fifths) according to Rule 4:–
By observing the conditions of Rule 11, the melody can only be arranged thus:–
For it is prohibited to be written thus:–
It follows, then, from these two methods, that the fifths are not saved; firstly, because in Example 34, the unison which occurs on the unaccented parts of the bars, cannot, on account of its nullity, either mitigate, or destroy, the effect of the fifth which precedes it, nor of that which follows it; secondly, because in Example 35, the interval of a third which intervenes between the accented and unaccented part of the bar, is too insignificant to work the desired effect.
There is a method by which several consecutive 15) fifths may be saved; thus:–
But this method is harsh and bold, inasmuch as between the first unaccented part and the second accented part, there occurs a movement prohibited by Rule 6. This expedient, therefore, is available to save two consecutive 16) fifths only, and not more; and even then, it must be in cases where the melody and the harmony violate no rule.
It may now be examined, whether, under favor of the precribed conditions, several successive octaves can be saved.
Fault (parallel octaves) according to Rule 4:–
By observing Rule 11, these means may not be employed:–
All the conditions are fulfilled by this method, and the octaves are saved, at least according to the rule:–
But even this method is not exempt from reproach, since, in order to save several octaves, two fifths are introduced in the two unaccented parts which succeed each other; and although whatever occurs in the unaccented part of a bar is not regarded with extreme rigour, yet the two fifths are not the less perceptible to the ear.
The following examples are better, because they offer no such objectionable point, and because they do not redeem one fault by other:–
Notwithstanding, it is to be observed, that this method of saving either two fifths or two octaves, was regarded by the ancient authors, as a reprehensible license, in two-part counterpoint. I am of the same opinion; and I think that two accented parts succeeding each other in fifth or in octave, whatever may be the intervening note placed on the unaccented part, the impression produced by the two fifths or two octaves is not destroyed; unless indeed the movement may be very slow, in which case each portion being taken for an entire bar, the unaccented parts may be computed by feeling, as so many accented ones. This reasoning, however, is specious, and should not pass into a law.
It is to be concluded, then, that the present rule must be applied only to composition in more than two parts; or else to employ it in this order but very rarely, and as a means of eluding some perplexing point.
These remarks and demonstrations upon the subject of two fifths and two octaves, have been set down, not so much for the sake of proving by example that they may be saved in a stated manner, as to show the little force of this rule, which I look upon as having been added to the severe rules of the ancient classical authors. Notwithstanding its want of force, however, it may occasionally be of some use.