A Dictionary of Music and Musicians/Canon
CANON. This is the strictest and most regular species of imitation. [See Imitation.] It is practised in music for two, three, or more parts. The word is derived from the Greek κανών, a rule or standard. A canon, therefore, is a composition written strictly according to rule. The principle of a canon is that one voice begins a melody, which melody is imitated precisely, note for note, and (generally) interval for interval, by some other voice, either at the same or a different pitch, beginning a few beats later and thus as it were running after the leader. For this reason the parts have been sometimes respectively called 'Dux' and 'Comes,' or 'Antecedens' and 'Consequens.'
The following is a simple example of a canon 'two in one at the octave,' i.e. for two voices an octave apart, and both uinging one and the same melody.
By means of a coda (or tail-piece) this canon is brought to a conclusion. But many canons lead back to the beginning, and thus become 'circular' or 'infinite.' The following is a specimen of this kind, which is 'two in one at the fifth below,' or 'canon ad hypodiapente':—
Sometimes two or more canons are simultaneously woven into one composition. The following, for instance (from Travers's Service, 1740), would be called a canon 'four in two.'
Byrd's 'Diliges Dominum,' for 8 voices, consists of 4 canons all sung together, each voice singing the melody of its fellow reversed.
Often in a quartet there may be a canon between two of the voices, while the other two are free; or three voices may be in canon and the fourth part free. We would quote as an example the admirable Gloria Patri to Gibbons's 'Nunc dimittis' in F, in which the treble and alto are in canon while the tenor and bass are free. Again, there are canons by inversion, diminution, augmentation, or 'per recte et retro,' cancrizans, &c. [See those headings.] A modern one of great ingenuity by Weber exists to the words 'Canons zu zwey sind nicht drey' (Jahns, No. 90).
The old writers often indicated canons by monograms, symbols, or other devices, instead of writing them out in full. Indeed they went so far as to write their indications in the form of a cross, a hand, or other shape, with enigmatical Latin inscriptions to indicate the solution. Such pieces were called 'enigmatical canons.' As compositions of this nature can only be regarded in the light of ingenious puzzles, bearing the same relation to music that a clever riddle does to poetry, it will be needless to give examples here, let it suffice to refer to those which are to be found in Fétis's admirable 'Traité du Contrepoint et de la Fugue,' and in Marpurg's celebrated work on the same subjects.
The great masters were fond of the relaxation of these plays on notes. They occur often in Beethoven's letters, and the well-known Allegretto Scherzando of his 8th Symphony originated in a canon to be sung at Maelzel's table. Köchel's Catalogue of Mozart's works contains 23 canons; that of Weber by Jähns, 8; and an interesting collection will be found in the Appendix to Spohr's Autobiography. In Bach's '30 Variations' there are 9.
As popular examples of canons may be named Byrd's well-known 'Non nobis Domine,' which is a canon three in one, in the fourth and eighth below, and Tallis's 'Canon,' which is a hymn-tune (usually adapted to Ken's evening hymn) in which the treble and tenor are in canon while the alto and bass are free. The lover of cathedral music will find specimens of almost every variety of canon in the service by Purcell in B♭, which is a masterpiece of ingenuity and skill. Other good specimens will be found in the Collection of his Gloria Patris, published by V. Novello for the Purcell Club. On the tablet erected in the cloisters of Westminster Abbey to the memory of Dr. Benjamin Cooke, organist of Westminster Abbey at the close of the last century, there is engraved a canon, three in one, by double augmentation, which is one of the best extant specimens of that kind of composition. Another, by Andre, 4 in one, by threefold augmentation, is given in Ouseley's 'Counterpoint, Canon, and Fugue,' example 12.
Canons are often introduced into fugues as the closest species of 'stretto' [see Fugue and Stretto], and are to be found both in vocal and instrumental compositions. As specimens of the former we would refer, in addition to the references given above, to many of Handel's choruses, especially to one in Judas Maccabaeus, 'To our great God,' which contains a canon by inversion; also to Sebastian Bach's magnificent cantata on the chorale 'Ein' feste Burg.' As specimens of instrumental canons we would refer to the first movement of Mozart's sonata for pianoforte and violin in E minor; or to the minuet of Haydn's symphony in the same key.
The word 'canon' is also applied, somewhat incorrectly, to a species of vocal composition called a Round. And thus we have duets, trios, and quartets 'a canone,' especially in the works of modern Italian composers, which are not really canons, but a much freer and less scientific kind of music. Good examples may be quoted in Beethoven's 'Mir ist' (Fidelio), Curschmann's 'Ti prego,' Cherubini's 'Perfida Clori,' and Rossini's 'Mi manca la voce.'[ F. A. G. O. ]