About this work
This splendid work, scored for glass harmonica, flute, oboe, viola and cello was composed in May 1791, less than seven months before Mozart's death. This is not a mere novelty piece, but a truly moving and thoughtful composition, praised by Alfred Einstein as "one of his heavenly works, an instrumental counterpart to the Ave Verum (K.618, composed less than a month later), with an unearthly beauty...." The lovely, bittersweet Adagio opens with tragic chords. The music then alternates between solo passages for the glass harmonica, which gradually increase in their degree of ornamentation, and operatic duet melodies for flute and oboe. After a recapitulation of the theme, there are several chromatic runs for solo instruments, and the glass harmonica has a chance to show that its felicity in executing complex passages is equal to the standard instruments. The Rondo opens with a light and pastoral music box solo for glass harmonica, this then repeated by the other instruments. The second theme (B) is a slow descending passage in thirds which trails back into the main theme in an unexpected jolly turn. After the recapitulation, the segue recalls the descending thirds but has an inverted pedal point above giving the passage a especially heavenly quality. An extended elaborate solo for glass harmonica follows, the theme is repeated by the other instruments, and a chordal idea (C) follows. The theme is varied by the glass harmonica, and the other instruments create an elaborate passage with many suspensions and hints of double counterpoint. Instruments are featured in arpeggios, the main theme is repeated in its original unadorned manner. A coda-like section follows with pulsing from the strings (on the tonic and dominant chords over a tonic pedal point) and a unique timbral effect is created when the other instruments are added into the mix. The C-theme is repeated and elaborated upon briefly, and then the piece closes with a brief and delicate coda.