Samuel P. Langley (1834-1906) was the third Secretary of the Smithsonian Institution. Apparently, many of Langley's papers were accidentally burned after his death. Langley papers in the Smithsonian are housed in the Smithsonian Archives and the National Air and Space Museum (NASM). The Allegheny Observatory holds papers from Langley's years there, from which copies of Langley's correspondence, 1867-1887, have been made for this collection.
These papers document important aspects of Langley's scientific and administrative career. Most of the material documents the progress of his aeronautical research from his first flying model of 1891 through the failure of his Aerodrome A of 1903. Also, information files housed in the National Air and Space Museum Library include secondary accounts and photographs relating to Langley's aeronautical studies. Related materials in the NASM Library include the Stephen M. Balzer papers, 1898-1902, which consist of correspondence with Langley and his associate, Charles M. Manly, regarding Balzer's aerodrome engines.
Materials in this collection consist of publications, including a bound collection of writings, and original manuscripts of many of Langley's publications, 1869-1905; diaries and shorthand notebooks, mostly kept by Langley's secretary, 1889-1905; bolograph curve and line spectrum readings; microfilm and photocopies of Langley's outgoing correspondence from the Allegheny Observatory, 1867-1887; astrophysical research correspondence; scrapbooks, 1890-1903; aeronautical research, including correspondence, wastebooks, and notes of Langley and Manly and their assistants, E. C. Huffaker, L. C. Maltby, B. L. Rhinehart, and R. L. Reed; and oversize aerodrome drawings and bolometer readings.