other Part, while the other Parts fill up the Harmony, in accordance with the laws already laid down, as at (e), in Ex. 3. If the last Chord be not naturally Major, it must be made so, by an accidental Sharp, or Natural.[1]
Second Order (Two notes against one). In this Order, two Minims must be written, in one of the Parts, against each Semibreve in the Canto fermo, except the last, unless the Exercise should be in Triple Time, in which case, three Minims must be written against each Semibreve.[2] The other Parts must all move in Semibreves.
In the Part which contains the Minims, the same note may not be struck twice in succession.
The first bar should begin with a Minim Rest, followed by a Minim, in Perfect Concord.
In the remaining bars, the first Minim must always be a Concord, Perfect, or Imperfect.
The second Minim may be either a Concord, or a Discord. If a Concord, it may proceed either in Conjunct or Disjunct Movement.—Ex. 4 (g). If a Discord, it must be both approached, and quitted, in Conjunct Movement, and lie between two Concords. In other words, it must be treated as a Passing Note.—Ex. 4 (f).
The Part which contains the Minims is not permitted to make the leap of a Major Sixth under any circumstances; and not even that of a Minor Sixth, except as a last resource, in cases of extreme difficulty.[3] Consecutive Fifths and Octaves between the first Minims of two successive bars, are strictly forbidden. Between the second Minims they are tolerated, but only for the purpose of escaping from a great difficulty.
Except in the first and last bars, the Unison is forbidden, on the Thesis, or accented part of the measure; but permitted, on the Arsis, or unaccented beat. The Octave on the Arsis may be used, with discretion; but the Octave on the Thesis (Ital. Ottava battuta; Germ. Streich-Octav) is only permitted, when approached, as in the First Order, either in Oblique Motion, or by separation. Its employment by approximation, as in Ex. 4, bar 5, is permitted only in the Final Cadence.[4]
In these, and all other cases, the first Minims of the bar are subject to the same laws as the Semibreves of the First Order; and the more closely these laws are observed, the better the Counterpoint will be. If the elimination of the second Minim in every bar, except the first, and the last but one, should produce good Counterpoint of the First Order, no stronger proof of excellence can be desired.
The Cadence is treated like that of the First Order; one of the sounds necessary to form the characteristic Intervals being assigned to the Canto fermo, and the other, either to the Part which contains the Minims—Ex. 4 (h); Ex. 5 (i)—or to some other Part written in Semibreves.
Third Order (Four notes against one). In this Order, four Crotchets must be written, in one of the Parts, against each Semibreve in the Canto fermo, except the last; the other Parts moving in Semibreves.
The first bar should begin with a Crotchet Rest, followed by three Crotchets, the first of which must form a Perfect Concord with the Canto fermo.
The first Crotchet, in the succeeding bars, is subject to the same laws as the first Minim in the Second Order. The three remaining Crotchets may form either Concords or Discords, provided that, in the latter case, they proceed in Conjunct Movement, and lie between two Concords; in which respect they must be treated like the unaccented Minims in the Second Order.
When the second Crotchet forms a Discord with the Canto fermo, in a descending passage, it may, by Licence, fall a Third, and then ascend to the necessary Concord, as at (h) in Ex. 6, and (l) in Ex. 7. This very beautiful progression, though forbidden by Cherubini, is sanctioned by the universal practice of the Great Masters of the 16th century.'[5]
The employment of the Tritonus, or the False Fifth, as intervals of Melody, is forbidden, not only by leap, but even when the intervening sounds are filled in; thus, the progressions, F, G, A, B, and B, C, D, E, F, are as contrary to rule as F, B, or B, F. This law, however, is
