Duets and trios for stringed instruments were naturally held in less esteem than string quartets. Mozart composed in Vienna (September 27, 1788), for some unspecified occasion, a trio for violin, viola, and violoncello, in £ flat major (563 K.), which consists of six movements, after the manner of a divertimento--allegro, adagio, minuet, andante with variations, minuet, rondo. The omission of the one instrument increases the difficulty of composing a piece full in sound and characteristic in movement, more than could have been imagined; the invention and skill of the composer are taxed to the utmost. It is evident that this only gave the work an additional charm to Mozart. Each of the six movements is broadly designed and carried out with equal care and devotion, making this trio unquestionably one of Mozart's finest works. No one performer is preferred before the other, but each, if he does his duty, may distinguish himself in his own province. With wonderful discrimination, too, every technical device is employed which can give an impulse to any happy original idea. How beautifully, for instance, is the simple violoncello passage which ushers in the adagio--[See Page Images] transformed into the emphatic one for the violin-- coined in due time, with climacteric effect, by the viola and violoncello. The violin-jumps in the same adagio-- are effective only in their proper position; and all the resources at command are made subservient to the art which is to produce the living work. {MOZART'S INSTRUMENTAL MUSIC.} (18) The variations demand special attention. The theme is suggestive of a national melody, and its effect is heightened by the different treatment of each part when repeated, which also gives fulness and variety to the variations. Each of these is artistically worked out in detail and of distinctly individual character; the last is especially remarkable, in which the viola, to a very lively figure, carries out the theme in its simplest enunciation as a true Cantus firmus. The whole impression is one of freshness and beauty of conception, elevated and enlivened by the difficulties which offered themselves. Nothing more charming can be imagined than the first trio of the second minuet; its tender purity charms us like that of a flower gleaming through the grass. Haydn seems to have made no use of the increased resources offered by the quintet, although other musicians--Boccherini, for instance--cultivated this branch. It would appear to have been for some particular occasions that Mozart composed four great string quintets, in which he followed the track laid out in the first quartets. Two were composed in the spring of 1787, after his return from Prague--[24] C major, composed April 19, 1787 (515 K.). G major, composed May 16, 1787 (516 K.).-- the other two-- D major, composed December, 1790 (593 K.). E flat major, composed April 12, 1791 (614 K.).--