… a corset of course! By the early 1820’s, the metal grommet had been invented, allowing for tight lacing. By the 1840’s the corset had become a shaping instrument to mold the body to fashion.
The corset changed gradually between the early Victorian 1840’s into one with a tighter waist that was in the center vertically in the 1850’s and ’60’s.
(Sketch and 1840 corset: which solves the mystery of what women wore during their periods! Note the hook center front, presumeable to tie a rag or pad front and back… or perhaps it’s for post-birth bleeding since they had a LOT of children in those days).