at short intervals, "at the earnest solicitation of a musical friend," as the publisher's announcement declares.[25] Mozart doubles the viola[26]--not like Boccherini in his 155 quintets, the violoncello[27]--whereby little alteration in tone, colour, or structure is effected. The doubling of the violoncello gives it a predominance which its very charm of tone {THE QUINTET.} (19) renders all the more dangerous: whereas the strengthening of the less strongly accentuated middle parts by the addition of a viola gives freer scope for a lengthy composition. The additional instrument gives increase of freedom in the formation of melodies and their harmonic development, but it also lays on the composer the obligation of providing independent occupation for the enlarged parts. A chief consideration is the grouping of the parts in their numerous possible combinations. The first viola corresponds to the first violin as leader of melodies, while the second viola leaves the violoncello greater freedom of action; these parts share the melodies in twos or threes, either alternately or in imitative interweaving; the division of a motif as question and answer among different instruments is especially facilitated thereby. Again, two divisions may be placed in effective contrast, the violins being supported by a viola, or the violas by the violoncello. But the device first used by Haydn in his quartets, of giving two parts in octaves, is perhaps the most effective in the quintets, a threefold augmentation being even employed in the trio of the E flat major quintet (614 K.). Finally, it is easier to strengthen the violoncello by the viola here than it is in the quartet. It is not that all these resources are out of reach for the quartet, but that they find freer and fuller scope in the quintet. The effect of the quintet is not massive; it rests on the characteristic movement of the individual parts, and demands greater freedom in order that this movement of manifold and differing forces may be well ordered and instinct with living power. The increased forces require greater space for their activity, if only on account of the increased mass of sound. If the middle parts are to move freely without pressing on each other, the outer parts must be farther apart, and this has a decided influence on the melodies and the sound effects, the general impression becoming more forcible and brilliant. The dimensions must also be increased in other directions. A theme, to be divided among five parts, and a working-out which is to give each of them fair play, must be planned from the first. The original motif of the first Allegro of the C major quintet (515 K.)--[See Page Image] {MOZART'S INSTRUMENTAL MUSIC.} (20)