This Lady is probably Charlotte, wife of John Spencer, 5th Earl Spencer. They were married in 1858.
Posted to Live Journal lamodeillustrée blog by katmax1 on 10 July 2010; detail-enhanced by gogm.
Lady Spencer's dress has all of the crinoline era trimmings with bertha, engageantes, and a big, layered dome crinoline, all under a lace wrap. If a lady sought to make a grand impression, a frilly crinoline was helpful as seen in this photo or this one of Empress Carlota.
Keywords: Window, Countess, Spencer family, British, straight coiffure, tiara, off shoulder vee neckline, bertha, lace, engageantes, vee waistline, crinoline, flounces, bodice ornament, necklace, earrings, gloves, fan