Portrait of Pierre Jules Cesar Janssen. Born 22 February 1824 in Paris, France. Died 23 December 1907 in Meudon, France. Photograph after Gaspard-Felix Tournachon, Nadar (1820-1910), c. 1900. Reasonable condition. Some minor soiling. Faint traces of wear along edges. Mounted onto an old album leaf. Dimensions: 76 x 43 mm. Pierre Jules Cesar Janssen was Astronomer, Photographer, Discovered the gaseous nature of the solar chromosphere, Discovered helium, and First director of Meudon Observatory.