e Greek
[Greek: Kanon], meaning a strict rule or law) is a composition in
which there is a _literal_ systematic imitation, carried out to the
end, between two or more of the voices (often with subsidiary voices
filling in), and may be considered a kind of musical dialogue in which
the second, or answering, part reenforces the message previously
uttered by the leading voice. This imitation may take place at any
degree of separation; and Canons are in existence at the interval of
the second, third, fourth, fifth, etc. The most effective Canons,
however, are those in which the answering voice is an octave away from
the leading one. Although the Canon is not a form employed frequently
by modern composers for an entire composition, Canonic imitation
appears so often in all large works for orchestra, string quartet or
ensemble combinations, that the music-lover should acquire a certain
ease in listening to a structure of this type. The Canon, moreover, is
an integral factor in the style of Cesar Franck, d'Indy and Brahms;
and illustrations of its use abound in their works. The organ is
particularly well suited to the rendition of Canons; since, by its
facilities for tone-color, the two voices may be clearly contrasted.
Those interested in organ literature should become acquainted with the
following excellent examples: The _Canon in B-flat major_, op. 40, by
Guilmant; the 4th movement of the _Fifth Organ Symphony_ by Widor; the
Canon in B minor, op. 54, by Schumann; the _Canon in F-sharp major_,
op. 30, by Merkel, and the set of _Ten Canonic studies_, op. 12, by
G.W. Chadwick. In other fields of composition the following should be
cited: The set of _Pianoforte Pieces in Canon form_, op. 35, by
Jadassohn; a like set by Rheinberger, op. 180; the _Canonic Vocal
Trios_, op. 156, by Reinecke and the famous Canon from the first act
of Beethoven's opera _Fidelio_. There is also a beautiful bit of
Canonic imitation between two of the upper voices in the introduction
of Berlioz's _Carnaval Romain Overture_ for orchestra. One of the most
appealing Canons in modern literature is the setting for soprano and
barytone, by Henschel, of the poem _Oh that we two were Maying_ by
Charles Kingsley. This example alone would sufficiently corroborate
the statement that the firmness of structure inherent in the canonic
form is perfectly compatible with genuine freedom and poetry of
inspiration. In the first movement of Cesar Frank's _Symphony in D
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