Both floors of the tribune are shown in section and the finishings to the first floor are included in the drawing and marked C, D, E and F on the section. The tribune was lit by a lantern with coloured glass.

The verso of drawing 105 has a full size detail of the mouldings at the base of the lantern, marked C on the section. It consists of a frieze that resembles the soffit of a Greek order, with panels of ball mouldings alternating with plain panels sunk 1/4 inch. The recto has details for the surbase that surrounds the room at the level of the pilaster capitals.

The ceiling of the lantern has a bell light in its centre, marked 'bell glass' on the drawing. Later drawings also include this detail, indicating that it was executed. Soane's bell lights are usually employed as skylights in tight secondary spaces and so this design is notable.