The movement begins with a slow introduction which quickly switches between the forte tutti and the piano monophonic passages. The melody of the introduction finishes on a dominant seventh chord, decorated with an arpeggio by the clarinet.
After the introduction, the septet carries on in sonata form. The exposition begins with a sequential first idea which then leads into a series of chromatic passages. The first idea is then repeated by the clarinet with a syncopated accompaniment played by the strings. The second subject begins at bar 53 In the dominant key of B flat major with a homophonic texture of three part strings. When the four bar phrase is repeated by the woodwind, the strings have a more lively quaver accompaniment. At bar 61 another second subject theme appears, shared between violin and clarinet, which is doubled by the bassoon. At bar 76 the violin has a 4 bar sequence of triplets ending in the fifth bar on a descending dominant seventh chord. The third theme is introduced at bar 86. It is a staccato chordal phrase. It is repeated at bar 90 in sequence at the original pitch but with varied harmony. The subject is finished with a cadential 6-4 In bars 97-98.
The codetta begins at bar 98 beat 3. It reinforces the established dominant key. The one bar phrase at the start of this section is repeated over a pedal note of B flat played by the horn and then the double bass as well. The exposition ends at bar 107-111 with three perfect cadences.
The development begins with the opening of the first subject in octaves by every instrument except the double bass and horn, and a rapid key change to c minor. At bars 116- 120 the melody from the codetta is heard on the clarinet and then is heard again in sequence on the horn. The music then begins to modulate between many keys. At bar 125 the idea from bar 40 is heard again, alternating with the codetta theme until a pedal note in bar 140 brings the return of the tonic key. Over the pedal note is the theme...