ACIS AND GALATEA. A 'masque,' or 'sereriata,' or 'pastoral opera,' composed by Handel at Cannons, probably in 1720 (date is wanting on autograph); and performed there probably in 1721. Words by Gay, with additions by Pope, Hughes, and Dryden. Re-scored by Mozart for Van Swieten, Nov. 1788. Put on the stage at Drury Lane by Macready, Feb. 5, 1842.—'Aci, Galatea, e Polifemo,' an entirely different work, was composed in Italy in 1708-9.
ACT. A section of a drama having a completeness and often a climax of its own. Though the word Act has no representative in Greek, the division indicated by it was not unknown to the ancient theatre, where the intervention of the chorus stopped the action as completely as the fall of the curtain in the modern. The 'Plutus' of Aristophanes, the earliest Greek play from which the chorus was extruded, has come down to us without breaks or divisions of any kind; practically, therefore, it is 'in one act.' Whether the earlier essays of Roman dramatists were divided into acts by themselves is uncertain. The canon of Horace, that a drama should consist of neither more or less than five acts ('Epist. ad Pisones,' 189), was doubtless drawn from previous experience and practice.
The number of acts into which the modern drama is divided, though of course largely dependent on the subject, is governed by many considerations unknown to the ancient, in which 'the unities' of place as well as of time and action was strictly observed. With us the locality generally changes with each act, frequently with each scene. For this change the convenience of the mechanist and even of the scene-shifter has to be consulted. In the musical drama other considerations beside these add to the difficulties of laying out the action; such as variety and contrast of musical effect, and the physical capabilities of the performers, whose vocal exertions must not be continued too long without interruption. It is not surprising therefore that operas, even of the same class, present examples of every kind of division. French 'grand opera' consists still generally, as in the days when Quinault and Lully worked together, of five acts; French 'opéera comique' of three, and often one only. The Italians and Germans have adopted every number of acts, perhaps most often three. In performance the division into acts made by the author or composer is frequently changed. Mozart's 'Nozze di Figaro,' originally in four acts, is now generally played in two; and Meyerbeer's 'Huguenots,' originally in five, in four.
The curtain let down between the acts of a drama is called in the theatre 'the act drop.'
Handel (Schoelcher, 288, etc.) applies the word to oratorios, and it is used by J. S. Bach in a manner probably unique. He heads his cantata 'Gottes Zeit ist das allerbeste Zeit' with the words ' Actus Tragicus.' It is what would be called among ourselves a funeral anthem.
ACTION (Fr. Le Mécaniqne; Ital. Mecanica; Ger. Mechanismus, Mechanik), the mechanical contrivance by means of which the impulse of the player's finger is transmitted to the strings of a pianoforte, to the metal tongue (free reed) of a harmonium, or by the finger or foot to the column of air in an organ-pipe. In the harp the action, governed by the player's foot upon the pedals, effects a change of key of a semitone or whole tone at will. In the pianoforte the action assumes special importance from the capability this instrument has to express gradations of tone; and as the player's performance can never be quite consciously controlled—more or less of it being automatic—we are, through the faithful correspondence of the action with the touch, placed in direct relation with the very individuality of the player. It is this blending of conscious and unconscious expression of which the pianoforte action is the medium that produces upon us the artistic impression. There have been important variations in the construction of pianoforte actions that have had even geographical definition, as the English, the German action, or have been named from structural difference, as the grasshopper, the check, the repetition action. In the organ and harmonium, as in the old harpsichord and spinet, the action bears a less important part, since the degree of loudness or softness of tone in those instruments is not affected by the touch. For history and description of the different actions see Clavichord, Harmonium, Harp, Harpsichord, Organ, and Pianoforte.
ACUTENESS. A musical sound is said to be more acute as the vibrations which produce it are more rapid. It is said to be more grave as the vibrations are slower. Thus of the two notes
and
the former of which is produced by 512 vibrations per second, and the latter by 256, the former is called the more acute, the latter the more grave. The application of these terms is not easy to account for. 'Acute' means sharp in the sense of a pointed or cutting instrument, and 'grave' means heavy; but there is no direct connection between the impression produced by rapid vibrations on the ear and a sharp edge, nor between the effect of slow vibrations and the force of gravitation; neither are these terms consistent, for one is not the antithesis to the other. To be correct, either the slow vibration-sound should be called 'blunt,' or the quick one 'light.' The terms however are as old as the Greeks, for we find them applied in the same way by Aristides Quintilianus, who uses ὀξύς to denote the quick vibrating sounds, and βαρύς to denote the slow ones, and they have been transmitted through the Latin acer and gravis down to our day. Other figurative terms are similarly applied. 'Sharp,' for example, is clearly synonymous with 'acute,' both in derivation and application; but 'flat' has no analogy with grave or heavy. It is a more correct antithesis to acute or sharp, for one can fancy a blunt edge to be in some degree
