?-? Harpers Ferry, Va., Bollman 1/148' Arsenal Branch, B. & O. Arsenal Canal through RR. Skew type. Span truss length is that of previous timber span. ?-? Baltimore, Md., Bollman 2/? B. & O. RR. Gwynns Falls through truss BIBLIOGRAPHY _A history and description of the Baltimore and Ohio Railroad by a citizen of Baltimore._ Baltimore, 1853. Baltimore and Ohio Railroad Company. _A list of the officers and employees of the Baltimore and Ohio Railroad for November, 1857._ Baltimore, 1857. ----. _Third annual report of the president and directors to the stockholders of the Baltimore and Ohio Rail Road Company._ Baltimore: 1829. (Also the fourth through 38th annual reports. Baltimore, 1830-1864.) ----. _Baltimore and Ohio exhibits at the Century of Progress._ Chicago, 1934. _Biographical cyclopedia of representative men of Maryland and the District of Columbia._ Baltimore, 1879. BOLLMAN, WENDEL. _Iron suspension and trussed bridge as constructed for the Baltimore and Ohio Rail Road Co. at Harper's Ferry, and on the Washington branch of this road._ Baltimore, 1852. ----. Letter to John W. Garrett dated June 17, 1862. In files of Division of Mechanical and Civil Engineering, United States National Museum, Washington, D.C. ----. _Report of Mr. Bollman in relation to Central Ohio Rail Road._ Baltimore, 1854. BRYANT, WILLIAM C. _Picturesque America._ New York, 1874. CLARKE, THOMAS CURTIS. _An account of the iron railway bridge across the Mississippi River at Quincy, Illinois._ New York, 1869. COLBURN, ZERAH. American iron bridges. _Minutes of the proceedings of the Institution of Mechanical Engineers_ (1863), vol. 22, pp. 540-573. CONDIT, CARL. _American building art:--The nineteenth century._ New York: Oxford Press, 1960. GRAY, GEORGE E. Notes on early practice in bridge building. _Transactions of the American Society of Civil Engineers_ (1897), vol. 37, pp. 2-16. GREINER, JOHN E. The American railroad viaduct--Its origin and evolution. _Transactions of the American Society of Civil Engineers_ (1891), vol. 25, pp. 349-372. LANG, PHILIP GEORGE. Bollman trusses on Valley of Virginia Branch will soon be memories. _Baltimore and Ohio Magazine_ (October 1923), pp. 18-19. ----. The old Baltimore and Ohio bridge crossing the Potomac River at Harpers Ferry, West [sic] Virginia. _Engineering News-Record_ (September 17, 1931), p. 446. MALEZIEUX, EMILE. _Travaux publics des Etats-Unis d'Amerique en 1870._ Paris, 1873. MCDOWELL, W. H. Unpublished engineer's report to the president and directors of Wilmington Railway Bridge Company, Wilmington, North Carolina, dated March 12, 1868. Typewritten copy in files of Division of Mechanical and Civil Engineering, U.S. National Museum, Washington, D.C.