are played by percussion—the Pianoforte and the Dulcimer; in the former the strings are struck by hammers attached to the keys, and in the latter by two hammers held in the hands.
3. Instruments of Percussion (Ger. Schlaginstrumente; Ital. Stromenti per la percussione; Fr. Instruments à percussion). These are of two kinds, those whose chief use is to mark the rhythm, and which therefore need not, and in many cases do not, give a note of any definite pitch, and those which consist of a series of vibrating bodies, each giving a definite note, so that the whole instrument possesses a scale of greater or less extent. Of the instruments of indefinite pitch, some are struck with drumsticks or other suitable implements; these are the Bass Drum, Side Drum, Tambour de Provence, Gong or Tam-tam, and Triangle; others, such as Cymbals and Castagnettes, are used in pairs, and are played by striking them together; and one, the Tambourine, or Tambour de Basque, is struck with the open hand. The instruments of percussion which give definite notes, and which are therefore musical rather than rhythmical, are the Kettle Drums (used in pairs, or more), Glockenspiel (bells used in military bands and occasionally with orchestra), and the Harmonica, consisting of bars of either glass, steel, or wood, resting on two cords and struck with a hammer.
4. There are still one or two instruments to be mentioned which are not easily classed in any of the three categories just described. In the Harmonium, which we have accepted as a windinstrument, the sound is really produced by the vibrations of metal springs, called reeds, though these vibrations are certainly excited and maintained by the force of wind; so also stretched strings may be acted upon by wind, and of this the Æolian Harp is an illustration. [See Æolian Harp.] The instrument or organ of Mr. Baillie Hamilton, which is said to be a combination of tongue and string, is not sufficiently perfected to be described here.
Metal tongues or reeds may also be played by plucking, and this method is employed in the so-called Musical Box, in which a series of metal tongues are plucked by pins or studs fixed in a revolving barrel. Another instrument played by plucking, but possessing only a single reed or tongue, is the Jews-harp. In respect to the production of its various notes this instrument differs from all others. It is played by pressing the iron frame in which the reed is fixed against the teeth, and while the reed is in a state of vibration altering the form of the cavity of the mouth, by which means certain sounds of higher pitch than the fundamental note may be produced, and simple melodies played. These higher sounds appear to be upper 'partial-tones' of the fundamental note of the reed, which are so strongly reinforced by the vibrations of the volume of air in the mouth as to overpower the fundamental tone, and leave it just audible as a drone bass. In the Harmonica proper, another mode of sound-production is employed, the edges of glass bowls being rubbed by a wetted finger. [See Harmonica.]
For much of the information contained in this article the writer is indebted to Schilling 'Universallexicon der Tonkunst.'
[ F. T. ]
INSTRUMENTATION, see Orchestration.
INTERLUDE (Germ. Zwischenspiel). A short Voluntary, played, by English Organists of the older School, between the verses of a Hymn, or Metrical Psalm.
Fifty, or even thirty years ago, a good extempore Interlude was regarded as no unfair test of an Organist's ability. The late Mr. Thomas Adams had a peculiar talent for Voluntaries of this kind: and, at S. Peter's, Walworth, John Purkis charmed his hearers, at about the same period, with delightful little effusions which were frequently far more interesting than the Hymns between the verses of which they were interpolated. Of late years, however, the Interlude has fallen so much into disuse that it is doubtful whether a good one is now to be heard in any Church in England.
In French Cathedrals, a long and elaborate Interlude is usually played, at Vespers, between the verses of the Magnificat, as well as those of the Hymn: and, at Notre Dame de Paris, S. Sulpice, and other Churches built on the same grand scale, where the Organ in the Choir is supplemented by a larger one at the western end of the Nave, a fine effect is sometimes produced by the alternate use of the two instruments; the smaller one being employed for the accompaniment of the voices, while the larger is reserved for the Interludes alone.
Interludes are played, in Germany, not between the verses of the Choral, but between the separate lines of each verse—an arrangement, which, however effective it may be in the hands of an accomplished Organist, is generally very much the reverse in those of a tyro. (Good examples are to be found in Ch. H. Rink's 'XXIV Choräle,' op. 64, 1804.) The delicious orchestral Interludes which embellish the Choral, 'Cast thy burthen upon the Lord,' in Mendelssohn's 'Elijah,' and those on a more extended scale in 'Nun danket' in the 'Lobgesang,' were evidently suggested by this old German custom; while the grand crash of brass instruments, introduced between the lines of 'Sleepers, wake!' in the same composer's 'S. Paul,' illustrates, perhaps, the most striking effect which it has yet been made to produce. [See Chorale.]
For an explanation of the word Interlude, in its dramatic sense, see Intermezzo.
[ W. S. R. ]
INTERMEZZO (Fr. Intermède. Entr' Acte. Old. Eng. Enterlude). I. A dramatic entertainment, of light and pleasing character, introduced between the Acts of a Tragedy, Comedy, or Grand Opera; either for the purpose of affording an interval of rest to the performers of the principal piece; of allowing time for the preparation of a grand scenic effect; or, of relieving the attention of the audience from the excessive strain demanded by a long serious performance.
The history of the Intermezzo bears a very important relation to that of the Opera; more