Half plate daguerreotype seated portrait of a likely teenaged girl sitting in a high-backed armchair with her arms crossed over her lap, all artistically side lit. (Tarnishing along edge, minor spotting, oxidation to mat, no preserver present; resealed.) Housed in a pressed paper case with floral design. Velvet pad stamped "W. & F. Langenheim, 216 Chestnut St., Philadelphia." 

William Langenheim (1807-1874) and Frederick Langenheim (1809-1879) were born in Germany and immigrated to the United states in the second quarter of the 19th century. The two opened a daguerreotype studio in Philadelphia in the early 1840s, and soon became celebrated portrait artists in the city. Pioneers in multiple techniques including hand-coloring daguerreotypes and producing negative and positive images on glass, the brothers are perhaps best known for being the first to publish stereoviews in the United States in 1854.