From the museum's Web site via pinterest.com/tamyamaunder/the-georgians.
Georgiana is the poster girl for 1780s bouffant coiffures. Hair expands out rather than up.
Keywords: 1783, Nixon, Georgiana Duchess of Devonshire, Georgiana Spencer, Duchess of Devonshire, Duchess, Spencer family, Cavendish family, British, long curly coiffure, ribbon headdress, scoop neckline, full sleeves