"in her enormous Bath chair"

Bath chair, St John's Museum Store, Bath
Creative Commons AttributionBath chair, St John's Museum Store, Bath - Credit: Rwendland
A bath chair is a light carriage, used especially by invalids.  It was invented by James Heath, of Bath, England.  The original version was mounted on four wheels and drawn by a horse or donkey.  It was later adapted to be more like a wheelchair, pushed by a person rather than pulled by an animal. In the 19th century bath chairs were common at spa resorts.