An English engineer born in Belfast. A graduate of Cambridge, he was appointed as the first professor of engineering at the University of Manchester in 1868, where he remained for 37 years. He studied a wide range of engineering problems and his most notable work was in the field of hydrodynamics. He studied cavitation in hydraulic machines, designed the first multistage centrifugal pump, and patented the use of guide vanes in centrifugal pumps, which are still used today. The Reynolds number is named after him. He was elected a member of the Royal Society in 1877.