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Robert Manning (1816-1897) wrote his first paper on hydraulics in 1851 and his last in 1895. During this period, Manning devoted considerable effort to the development of a simple, dimensionally homogeneous formula for open-channel flow.

Born in Normandy, Manning and his mother moved to Waterford, Ireland, in 1826 after the death of his father. He worked as an accountant for his uncle, John Stephans, from 1834 through 1845, and was drafted into the Arterial Drainage Division of the Irish Office of Public Works in 1846 due tSample Imageo an expansion of this office during the Irish famine years. He served as a clerk, accountant, and draftsman until he was appointed assistant engineer to Samuel Roberts later that year. Upon Roberts' transfer in 1848, Manning was appointed as District Engineer, a position he held until 1855.

From 1855 to 1869, Manning was engaged by the Marquis of Downshire, during which time he conducted surveys of estates in Ireland, oversaw construction of the Dundrum Bay Harbor, and designed a water supply system for the city of Belfast. Manning was not reappointed to the position after the Marquis' death, so he returned to the Office of Public Works in 1869 as Assistant to the Chief Engineer. He was appointed Chief Engineer in 1874, and held this post until his retirement in 1891. As Chief Engineer, he was responsible for numerous harbor, navigation, arterial drainage, and sewerage projects. It is interesting to note that Manning received no formal training in fluid mechanics or engineering and would have likely remained an accountant/clerk had it not been for the Irish famine. In his writings he continually refers to the great pioneers of hydraulic engineering and theory: Chezy, Du Buat, and Eytelwein, as well as to his contemporaries: Darcy, Bazin and Kutter. It is obvious that his accounting background and pragmatism influenced his work. He had a strong drive to reduce problems to their simplest form, and he expressed disdain for mathematical formulations.