Two Movements: Slow ("Diapasons") and Allegro ("Trumpet" and "Stopt Diapason"). Slow Swell Open Diapason 8' + Principal 4' coupled to Great Open Diapason 8' + Principal 4'. Allegro SW Gedact 8' (B & T) + Viola di Gamba 8', GT Trumpet 8' or Stop Diapason 8' (B & T) + Flute 4'. In Allegro uncoupled Bourdon 16' doubles bass line ad lib, usually but not exclusively in Trumpet sections.