IAMBIC. An Iamb or Iambus is a metrical foot consisting of a short and a long syllable—as bĕfōre ; or as Coleridge gives it,
'Ĭāmbĭcs mārch frŏm shōrt tŏ lōng.'
This, from Handel's Alexander's Feast, is an iambic passage. So also is 'Rejoice greatly' from the Messiah. So is the following from the Finale to Beethoven's Kreutzer Sonata' (op. 47).
IASTIAN MODE. [See Ionian.]
IDEA, a theme or subject.
IDOMENEO RÉ DI CRETA, ossia Ilia e Adamante, an opera seria in 3 acts; music by Mozart. Composed at Salzburg in 1780, and produced at Munich, Jan. 29, 1781 (the 2nd day of Mozart's 26th year). The libretto was Italian, adapted by the Abbé Varesco (also author of that of 'L'Oca del Cairo') from a French piece of the same name by Danchet, which had been composed by Campra in 1712. Mozart's autograph is in the possession of André at Offenbach. Full score published by Simrock with Italian text. The opera contains a complete ballet in 5 numbers (autog. André) which has not yet been printed, but is announced for publication in the new edition of Breitkopfs.
Idomeneo has never been a favourite opera. The Allg. Musik. Zeitung during 50 years only chronicles 16 performances, and it appears never to have been put on the stage either in Paris or London. It has been twice newly arranged—by Treitschke (Vienna, 1806), and by Lichtenthal (Milan, 1843). Mozart himself felt that some improvements were wanted, as he speaks (Letter, Sept. 12, 1781 ) of rewriting the part of Idomeneo and making many alterations 'in the French style.'
IFIGENIA. The story of Iphigeneia, the daughter of Agamemnon and Clytemnestra—in the two episodes of her deliverance from sacrifice at Aulis, and her rescue of her brother Orestes from the same fate at Tauris, which formed the subject of Euripides' two tragedies—has been a favourite subject with the composers of operas. Not to speak of the two masterpieces of Gluck, which are noticed under the head of Iphigenia, we may say here that the opera of 'Ifigenia in Aulide' by Apostolo Zeno has been, according to the Catalogue in the Theatre Lyrique of F. Clement, set to music by no fewer than 20 composers between 1713 and 1811—D. Scarlatti, Caldara, Porpora, Abos, Traetta, Majo, Guglielmi, Jommelli, Salari, Sarti, Martin y Solar, Prati, Giordani, Zingarelli, Bertoni, Mosca, L. Rossi, Trento, Mayer, Federici. The opera of 'Ifigenia in Tauride' (author unknown, but possibly Vinci) has been composed by 9 separate composers—D. Scarlatti, Orlandini, Vinci, Jommelli, Mazzoni, Agricola, Monzi, Tarchi, and Carafa.
ILE ENCHANTÉE, L'. A ballet by Arthur Sullivan, produced at Covent Garden May 14 [App. p.684 "May 16"], 1864.
IMBROGLIO, i. e. confusion. A passage, in which the vocal or instrumental parts are made to sing, or play, against each other, in such a manner as to produce the effect of apparent, but, really, well-ordered confusion. A fine passage of this description occurs in the overture to 'Der Freischütz, at bars 145–154 of the Molto Vivace, though little trace of its intention is conveyed by the Pianoforte arrangement.
[ W. S. R. ]
IMITATION is a name given to one of the most useful and indeed necessary devices in contrapuntal composition. It consists in a repetition, more or less exact, by one voice of a phrase or passage previously enunciated by another, e.g.—
In the former of these examples the imitation takes place at one bar's distance, and at the interval of an eleventh above. In the latter it is at the interval of an octave below.
If the imitation is absolutely exact as to intervals it becomes a Canon. But in the majority of cases imitations are not canonical. Imitations may take place at any interval or at any distance. They may also be sustained by any number of voices or instruments, e. g.—
where we have an imitation in four parts.
- 'Metrical feet-Lesson for a boy.' Poetical Works. 11 145.