4. Allegro non troppo

Form

Sonata
Essentially monothematic
False reprise

Theme (A)

Breaks into two fundamental motives: first 4 and last 5 notes

Theme (E)

Constrating key and rhythmic pulse - 8ths notes

Development - New Material

Coda (A) - the last measure

Ending where we started: the 1st 4 notes including the contrasting rhythmic pulse

Notes

The finale of this quartet appears to recall its open movement with two simple details. Like the opening theme of the quartet, this theme starts with a chromatic descent. Even more interesting is the fact that the the first phrase falls into two motives, the second of which is essentially identical to the crucial second motive of the 1st movement. That the atomic particles of both movements are so alike, and that the developments are similar with their emphasis on these respective motive pairs inclines one to say that both movements are isopmorphs of a shared principle or ideal. The cross-linkages, the unity that spans the sectional diversity of the composition, reveals a detail of craftsmanship that is a chief higher order delight of the string quartet genre. It does much to supply one answer to question of whether movements within a quartet are related beyond the constellation of related keys and an often formulaic contrast of rhythm and mood.

Unlike the 1st movement, this sonata is essentially monothematic. The second key area (the dominant) is confirmed with the first theme transposed, with the subtle contrast of a heighthened eighth note pulse in the base.

Another detail that delights is the ending of the movement. The final few measures of the coda (itself atypical of Mozart's quartets), end not with a forte flourish of final cadences, but with a very soft, ultimate whisper of the first four notes. Initially, they carried the chromatic tension of the first steps in an adventurous departure. Here, they sigh with the release of the final few steps into rest. Gentle, gallant, witty it its restrait, it is the subduded signature of a master player upon finishing a brilliant game.

The development includes the brief appearance of entirely new material, a spacious song in half and whole notes that peaks the journey with an extra grandeur just before the recapitulation. A random treat, common to Mozart's ceaseless lyricism? A reference to a more meaningful topical interest lost on more modern ears? Maybe a deeper mystery that reveals another relationship of the part to the whole. It is noteworthy, but I know not exactly why.