The Gloria in excelsis, and Credo, have fixed Intonations of their own, which may be found in their proper places, in the Missal.
It is always interesting to observe the use made, by modern composers, of antient materials: and we shall find that some of the Intonations given, in our examples, have been turned, by the greatest Masters of the modern School, to very profitable uses indeed. For instance, Handel, in 'The Lord gave the word,' from 'The Messiah,' uses the Intonation of the First Tone, transposed a fourth higher, with wonderful effect—
etc.
while that of the Eighth (as sung to the Magnificat) has been employed, in a very striking manner, by Mendelssohn, in the 'Lobgesang'—
etc.
We have selected these instances from innumerable others, not only because the chief interest of the works mentioned is centred in these few simple notes; but because, in both cases, the phrases in question are really used as Intonations—i.e. as initial phrases, given out in unison, to be continued in harmonious chorus. Whether the composers were conscious of the source of the ideas they treated with such masterly power, is a question open to argument: but, there can be no doubt that John Sebastian Bach, when writing his great Mass in B minor, chose the opening subject of his magnificent Credo, simply because it was the Intonation assigned to the Credo in the Plain Chaunt Mass—
etc.
That the effect with which Bach introduces this grand old subject was not lost upon Mendelssohn, is evident, from a passage in a letter written from Rome, by the last-named composer, to his friends in Germany (April 4, 1831).
II. The art of singing, or playing, correctly in tune. Thus, we say that the intonation of such and such a performer is either true, or false, as the case may be. For a detailed account of the conditions upon which perfect tune depends, see Temperament.
INTONING. The practice of singing the opening phrase of a Psalm, Canticle, or other piece of Ecclesiastical Music, not in full chorus, but, as a solo, or semi-chorus, assigned either to a single Priest, or to one, two, or four leading Choristers. The term is sometimes strangely misapplied. For instance, we are constantly told that the Litany, or even a whole Service, was 'intoned' by some particular person; when the word used should have been, in the one case, 'sung,' and, in the other, 'monotoned.'
INTRADA or ENTRATA. A term used for an opening movement, as by Beethoven for the introductory piece of the 'Battle-Symphony' of his Battle of Vittoria, or for the first movement of the Serenade, op. 25. 'Intrade' is used by Mozart for the overture of his 'Bastien' (K. 50); and 'Intrada o Concerto' by Bach for an independent movement (Cat. No. 117). [See Entree 2.] [G.]
INTRODUCTION. The main purpose of an Introduction in music is either to summon the attention of the audience, or to lead their minds into the earnest and sober mood which is fittest for the appreciation of great things. The manner in which these purposes are accomplished varies greatly with the matter which is to follow. If that be light and gay any noise will answer the purpose, such as brilliant passages or loud chords; but if it be serious it is manifest that the Introduction should either have proportionate inherent interest or such dignity of simplicity as cannot be mistaken for triviality. It is interesting to note the manner in which this has been carried out by great masters, and the more important relations which seem to subsist between a movement and its Introduction in their works.
In the first place there are many examples of simple signals to attention; such as the single independent chord which opens Haydn's Quartet in E♭ (Trautwein No. 33); the simple cadence which introduces his Quartet in C, op. 72 (Trautwein No. 16), and the group of chords with cadence which precedes the Quartet in B♭, op. 72 (Trautwein No. 12). These have no other relation to the movement than that of giving notice that it is about to commence, and are appropriate enough to the clear and simple form of the Haydn Quartet. Similar examples are to be remarked in very different kinds of music; as for instance at the commencement of the Eroica Symphony, where the quiet soberness of the beginning of the movement seems to call for some signal to attention, while its supreme interest from the very first seems to indicate that introductory elaboration would be out of place. In Chopin's Nocturne in B major [App. p.685 "Op. 62, No. 1"], again, it is not difficult to see the reason for the adoption of the two simple forte chords with which it is introduced; since the commencement of the Nocturne proper is so quiet and delicate that without some such signal the opening notes might be lost upon the audience; whilst a more developed Introduction would clearly be disproportionate to the dimensions of the piece.
In great orchestral works, such as symphonies, Haydn usually commences with a set and formal Introduction in a slow tempo, which marks the importance of the work, and by remaining so close to the principal key of the movement as
