PARR

PARR 20.03. 1880 Yonkers NY/USA 07.06. 1964 Yonkers NY/USA Harry Lilienthal Parr obtained both the AB and ME degrees from Columbia University, New York NY, in 1902 and 1904, respectively. He then was there assistant of the Mechanical Engineering Department until 1906, joined until 1907 the Power Specialty Co., New York City, became until 1912 instructor of mechanical engineering at Columbia University, was there assistant professor until 1921, associate professor until 1928, from when he took over there until retirement in 1946 as professor of mechanical engineering. He was in parallel consultant in his professional field. He was a Fellow of the American Association for the Advancement of Science AAAS, and member of the American Society of Mechanical Engineers ASME, and the American Physical Society APS. Parr was in charge of the mechanical laboratory of Columbus University. He spent the summer visiting engineering schools and industrial establishments in Europe, reporting that the Americans have learnt few until the start of World War I. However, the foreign methods were described not as useful as they might be by reason of limited American equipment compared to that abroad. Excellent European laboratories were described. His laboratory at Columbia was described especially poor in this regard, so that Parr intended to adopt German methods. The European instruction in engineering was considered particularly important with regard to mechanical engineering. In Germany again, he mentioned, they do not hesitate to state that mechanical engineering is the foundation of all their manufacturing success, a fact just as true in America, though then not really recognized and supported. Parr’s ideas can be considered ahead these of John R. Freeman (1855-1932), who made visits to Europe in the 1920s, and consequently established the Freeman Scholarship allowing for gifted American students access to hydraulic studies at European universities. Anonymous (1912). Prof. H.L. Parr. Columbia University Quarterly 15: 102-103. Anonymous (1921). Parr, Harry L. American men of science 3: 527. Science Press: New York. Anonymous (1959). Parr, Harry L. Who’s who in America 28: 2070. Marquis: Chicago. Anonymous (1964). Harry L. Parr. Mechanical Engineering 86(12): 106. Parr, H.L., Thurston, Jr., E.D., Herrick, A.L. (1927). Steam engines, boilers, pumps, turbines, gas engines. Dept. Mechanical Engineering, Columbia University: New York. Parr, H.L. (1937). Fluid flow analyzer. Mechanical Engineering 59(6): 437-439; 59(12): 960. Parr, H.L. (1940). Smoke ribbons test streamline design. Popular Science 137(7): 99. P

PARSHALL 02.07. 1881 Golden CO/USA 29.12. 1959 Fort Collins CO/USA Ralph Leroy Parshall obtained the BS degree from Colorado Agricultural College, Fort Collins CO, in 1904, specializing in civil and irrigation engineering. He was assistant at the Department of Physics there until 1906, assistant professor of civil engineering until 1913, assistant in irrigation investigations at the US Department of Agriculture until 1918, when taking over as laboratory head at the Experiment Station until his retirement in 1948. Parshall is known for two devices used in irrigation engineering, namely the Parshall flume, and the Vortex sand trap. Following the common ‘Venturi flume’ introduced by Victor M. Cone (1883-1970) in 1916, Parshall presented an alterative structure for measurement of discharge under field conditions. His original device consisted of a short contraction from the approach to the tailwater canal width involving at the throat section a drop to avoid submergence effects. The device was laboratory-tested resulting in a dischargehead equation which points at certain scale effects. Irrigation engineers therefore had a simple and quite accurate means at hand to measure a basic quantity of fluid flow, rendering the device attractive despite certain disadvantages. Parshall flumes were developed from the 1960s and essentially may still be seen in the field. The Vortex Sand Trap was developed by Parshall in the early 1930s. A horizontal vortex is generated by setting a conduit diagonally across a flume, whose top is open. Due to turbulent water flow at the pipe crest, bedload sediment is entrained by the tube of which the sedimentwater flow is thereby separated from the approach flow. Anonymous (1922). Parshall, Ralph L. Who’s who in engineering 1: 968. Lewis: New York. Anonymous (1949). Council celebrates 30th anniversary. Engineers’ Bulletin 33(10): 6. P Anonymous (1960). Ralph Parshall. Civil Engineering 30(3): 230. Parshall, R.L. (1925). The improved Venturi flume. Trans. ASCE 89: 841-880. Parshall, R.L. (1929). Discussion of Experiments on models of Pit River Dams. Trans. ASCE 94: 507-511. Parshall, R.L. (1931). Sand trap for canals works on vortex principle. Civil Engineering 1(5): 419-421. Parshall, R.L. (1947). Riffle deflectors and vortex tubes remove suspended silt and sand. Civil Engineering 17(12): 740-741. Parshall, R.L. (1948). The Parshall measuring flume. Reclamation Era 34(5): 97-98. P Parshall, R.L. (1952). Model and prototype studies of sand traps. Trans. ASCE 117: 204-213.