reputed invention of the accordion (q.v.), is constructed with a double action, the same note being produced on compressing and expanding the bellows, whereas in the German concertina or accordion two different notes are given out. Concertinas are made in complete families—treble, tenor, bass and double bass, having a combined total range of nearly seven octaves. The compass is as follows:—
The timbre of the concertina is penetrating but soft, and capable of the most delicate gradations of tone. This quality is due to a law of acoustics governing the vibration of free reeds by means of which fortes and pianos are obtained by varying the pressure of the wind, as is also the case with the double reed or the single or beating reed, while the pressure of the reed with the lips combined with greater pressure of wind produces the harmonic overtones which are not given out by free reeds. The English concertina possesses one peculiarity which renders it unsuitable for playing with instruments tuned according to the law of equal temperament, such as the pianoforte, harmonium or melodion, i.e. it has enharmonic intervals between G♯ and A♯ and between D♭ and E♭. The German concertina is not constructed according to this system; its compass extends down to C or even B♭, but it is not provided with double action. It is possible on the English concertina to play diatonic and chromatic passages or arpeggios in legato or staccato style with rapidity, shakes single and double in thirds; it is also possible to play in parts as on the pianoforte or organ and to produce very rich chords. Concertos were written for concertina with orchestra by Molique and Regondi, a sonata with piano by Molique, while Tschaikowsky scored in his second orchestral suite for four accordions.
The aeola, constructed by the representatives of the original firm of Wheatstone, is a still more artistically developed concertina, having among other improvements steel reeds instead of brass, which increase the purity and delicacy of the timbre.
CONCERTO (Lat. concertus, from certare, to strive, also confused with concentus), in music, a term which appears as early as the beginning of the 17th century, at first as a title of no very definite meaning, but which early acquired a sense justified by its etymology and became applied chiefly to compositions in which unequal instrumental or vocal forces are brought into opposition.
Although by Bach’s time the concerto as a polyphonic instrumental form was thoroughly established, the term frequently appears in the autograph title-pages of his church cantatas, even when the cantata contains no instrumental prelude. Indeed, so entirely does the actual concerto form, as Bach understands it, depend upon the opposition of masses of tone unequal in volume with a compensating inequality in power of commanding attention, that Bach is able to rewrite an instrumental movement as a chorus without the least incongruity of style. A splendid example of this is the first chorus of a university festival cantata, Vereinigte Zwietracht der wechselnden Saiten, the very title of which (“united contest of turn-about strings”) is a perfect definition of the earlier form of concerto grosso, in which the chief mass of the orchestra was opposed, not to a mere solo instrument, but to a small group called the concertino, or else the whole work was for a large orchestral mass in which tutti passages alternate with passages in which the whole orchestra is dispersed in every possible kind of grouping. But the special significance of this particular chorus is that it is arranged from the second movement of the first Brandenburg concerto; and that while the orchestral material is unaltered except for transposition of key, enlargement of force and substitution of trumpets and drums for the original horns, the whole chorus part has been evolved from the solo part for a kit violin (violino piccolo). This admirably illustrates Bach’s grasp of the true idea of a concerto, namely, that whatever the relations may be between the forces in respect of volume or sound, the whole treatment of the form must depend upon the healthy relation of function between that force which commands more and that which commands less attention. Ceteris paribus the individual, suitably placed, will command more attention than the crowd, whether in real life, drama or instrumental music. And in music the human voice, with human words, will thrust any orchestral force into the background, the moment it can make itself heard at all. Hence it is not surprising that the earlier concerto forms should show the closest affinity (not only in general aesthetic principle, but in many technical details) with the form of the vocal aria, as matured by Alessandro Scarlatti. And the treatment of the orchestra is, mutatis mutandis, exactly the same in both. The orchestra is entrusted with a highly pregnant and short summary of the main contents of the movement, and the solo, or the groups corresponding thereto, will either take up this material or first introduce new themes to be combined with it, and, in short, enter into relations with the orchestra very like those between the actors and the chorus in Greek drama. If the aria before Mozart may be regarded as a single large melody expanded by the device of the ritornello so as to give full expression to the power of a singer against an instrumental accompaniment, so the polyphonic concerto form may be regarded as an expansion of the aria form to a scale worthy of the larger and purely instrumental forces employed, and so rendered capable of absorbing large polyphonic and other types of structure incompatible with the lyric idea of the aria. The da capo form, by which the aria had attained its full dimensions through the addition of a second strain in foreign keys followed by the original strain da capo, was absorbed by the polyphonic concerto on an enormous scale, both in first movements and finales (see Bach’s Klavier concerto in E, Violin concerto in E, first movement), while for slow movements the ground bass (see Variations), diversified by changes of key (Klavier concerto in D minor), the more melodic types of binary form, sometimes with the repeats ornamentally varied or inverted (Concerto for 3 klaviers in D minor, Concerto for klavier, flute and violin in A minor), and in finales the rondo form (Violin concerto in E major, Klavier concerto in F minor) and the binary form (3rd Brandenburg concerto) may be found.
When conceptions of musical form changed and the modern sonata style arose, the peculiar conditions of the concerto gave rise to problems the difficulty of which only the highest classical intellects could appreciate or solve. The number and contrast of the themes necessary to work out a first movement of a sonata are far too great to be contained within the single musical sentence of Bach’s and Handel’s ritornello, even when it is as long as the thirty bars of Bach’s Italian concerto (a work in which every essential of the polyphonic concerto is reproduced on the harpsichord by means of the contrasts between its full register on the lower of its two keyboards and its solo stops on both). Bach’s sons had taken shrewd steps in forming the new style; and Mozart, as a boy, modelled himself closely on Johann Christian Bach, and by the time he was twenty was able to write concerto ritornellos that gave the orchestra admirable opportunity for asserting its character and resource in the statement in charmingly epigrammatic style of some five or six sharply contrasted themes, afterwards to be worked out with additions by the solo with the orchestra’s co-operation and intervention. As the scale of the works increases the problem becomes very difficult, because the alternation between solo and