For the dark colored dresses. 1890 corset with shoulder braces (which would be for posture rather than to hold the corset in place). Probably made by Williamson Corset and Brace Co. Philadelphia Museum of Art.
Victorian Steampunk Black Satin Corset with White & Black Bustle Skirt: corset is boned with steel boning. Has front busks (opening) and back lacing with 20 grommets. Skirt is taffeta Victorian damask black and white bustle skirt.