Equinoctial Ring Dial, German, 1713

Vertical brass disc, representing the meridian, turns within the outer gilt-brass ring to the appropriate latitude marked on the disc (aligned with the index mark below the suspension ring). The hours are marked on the silvered segment of a circle and the gnomon is the curved pointer above, which slides along the gilt date-scale to which it is attached. The gnomon and hour-scale fold flat in the plane of the meridian disc when not in use.