The Wagner is “a museum of a museum,” containing the nation's oldest intact natural history display. William Wagner began collecting natural history specimens during his trips to the Far East as an agent for Stephen Girard. In 1855 he incorporated the Wagner Free Institute of Science to give adult education in the sciences to working men and women, a mission that it still fulfills. The building contains two glorious spaces: the first-story lecture room and the museum that takes up the entire second story, capped by a robust exposed truss and surrounded by two tiers of galleries. The teaching collection is installed according to the nineteenth-century system of “systematics,” by which natural specimens are grouped according to their taxonomic features. This was the creation of Joseph Leidy, nationally prominent biologist, who was the Wagner's first curator. The initial branch of the Free Library of Philadelphia opened here two years later, later expanding into William D. Hewitt's library wing, which was intended to have a matching pavilion on the other side.