Imitations are sometimes conducted by contrary motion of the parts, or 'by inversion,' e.g.—
More rarely we meet with imitations per rectè et retrò or, as they are sometimes called, 'by reversion,' in which the antecedent, being read backwards, becomes the consequent:—
(These examples are all taken from Fétis.)
Imitations may also be made by inversion and reversion, or by 'augmentation,' or 'diminution.' It will be needless to give examples of all these different kinds. Good examples may be found in the theoretical works of Baltiferri, Azopardi, Zimmermann, Marpurg, Fux, and Cherubini. The Suites and Fugues of Bach, the Symphonies and Sonatas of Haydn, Mozart, and Beethoven are full of good examples of various kinds of imitation. In fact every classical writer, whether of vocal or instrumental music, has derived some of his finest effects from a judicious employment of such artifices. Every student of music must make himself familiar with these contrapuntal resources if he would fain scale the loftiest heights and make himself distinguished as a composer of high-class music.
IMMANUEL. Oratorio in 2 parts, words selected and music composed by Henry Leslie; produced at St. Martin's Hall, March 2, 1854.
IMMYNS, John, by profession an attorney, was an active member of the Academy of Ancient Music. Having in his younger days been guilty of some indiscretion which proved a bar to success in his profession, he was reduced to become clerk to a city attorney, copyist to the Academy, and amanuensis to Dr. Pepusch. He possessed a strong alto voice and played indifferently on the flute, violin, viol da gamba and harpsichord. At the age of 40, by the sole aid of Mace's 'Musick's Monument,' he learned to play upon the lute. In 1741 he established the Madrigal Society [see Madrigal Society.] In 1752, upon the death of John Shore, he was appointed lutenist of the Chapel Royal. He was a diligent collector and assiduous student of the works of the madrigal writers and other early composers, but had no taste whatever for the music of his own time. He died of an asthma at his residence in Cold Bath Fields, April 15, 1764.
His son John made music his profession, became a violoncellist and organist, and was organist of Surrey Chapel at the time of his death in 1794.
IMPERFECT (Lat. Imperfectus, Ital. Imperfetto). A term employed, in Music, in relation to Time, to Melody, to Cadence, and to Interval.
I. Time. Mediæval writers (accustomed to look upon the number Three—the Symbol of the Blessed Trinity—as the sign of Perfection) applied the term, Imperfect, to all rhythmic proportions subject to the binary division.
The notes of Measured Music were called Imperfect, when divisible into two equal portions. Thus, the Minim—always equal to two Crotchets only—was essentially Imperfect, in common with all other notes shorter than the Semibreve. The Large was also Imperfect, whenever it was made equal to two Longs; the Long, when equal to two Breves; the Breve, when equal to two Semibreves; and the Semibreve when equal to two Minims.
The Imperfection of the Minim, and Crotchet, was inherent in their nature. That of the longer notes was governed, for the most part, by the species of Mode, Time, or Prolation, in which they were written: for, Mode, Time, and Prolation, were themselves capable of assuming a Perfect, or an Imperfect form. In the Great Mode Imperfect, the Large was equal to two Longs only, and therefore Imperfect; while all shorter notes were Perfect, and, consequently, divisible by three. In the Lesser Mode Imperfect, the Large [App. p.684 "Long"] was, in like manner, equal to no more than two Breves. In Imperfect Time, the Breve was equal to two Semibreves. In the Lesser (or Imperfect) Prolation, the Semibreve was equal to two Minims.
But notes, even when Perfect by virtue of the Mode, Time, or Prolation in which they were written, could be made Imperfect; and that, in several different ways.
A Perfect note was made Imperfect, 'by position,' when another note, or rest, of half its value, was written either before, or after it; thus, the Semibreves, in the following example, though written under the signature of the Greater Prolation, were each equal to two Minims only—
Black square notes, though Perfect by the Modal Sign, became Imperfect, in like manner, when mixed with white ones: thus, in the following example, each white Breve is equal to
