VERSLUYS

NETHERLANDS (see also List of Individuals)

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4.9.1880 Groningen/NL - 1.3.1935 Amsterdam/NL

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Jan Versluys was educated as a mining engineer. He gained in 1916 the doctoral title at Delft University and then took several positions in mining and drinking water supply in the Netherlands, the Dutch East Indies and Surinam. Versluys finally joined the Bataafsche Oil Company in 1927 and lifted oil and gas exploration and exploitation to a scientific level. In 1918, he was the first lecturer in hydrology of the Netherlands, at Delft University. His appointment as professor of economic geology at the University of Amsterdam followed in 1932.

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Versluys may be considered the first Dutch general hydrologist. He was familiar with the hydraulic works of Slichter, Joseph Boussinesq (1842-1929) and Philipp Forchheimer (1852-1933). His 1916 PhD thesis on capillary phenomena in the soil forms one of the first systematic treatises of the subject matter. In the same year he presented the correct explanation for the occurrence of sodium bicarbonate in groundwater in the coastal zone. The sodium bicarbonate type of groundwater subsequently became an important tracer in reconstructing the evolution of fresh-saltwater distribution in coastal areas. Versluys also made clear that water in the unsaturated zone exerted a negative pressure relative to atmospheric pressure and thus could not flow at the surface in an excavation above the groundwater table. Although his work was of qualitative nature, it was based on sound physical principles and extensive observations produced by the US Department of Agriculture.

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_{Versluys, J., Steenhuis, J.F. (1915). Hydrologische bibliographie van Nederland. Versluys: Amsterdam.}

_{Versluys, J. (1916). De capillaire werkingen in den bodem. Academisch Proefschrift: Delft. Versluys, J. (1918). Hydrologie van het nederlandsche kustgebied. Moorman: s'Gravenhage. Versluys, J. (1918). De beginselen van de theorie der grondwaterwinning en der grondwaterverlaging. De Ingenieur 33(52): 1002-1003.}

_{Versluys, J. (1919). Grondwaterbeweging tusschen kanalen met verschillende waterstanden. De Ingenieur 34(24): 454-456.}

_{Versluys, J. (1923). De zuivering van rivierwater in Soerabaja. Soerabaja.}

_{Versluys, J. (1923). Het snelfilter der gemeentelijke waterleiding te Soerabaja. De Ingenieur}

_{38(29): 585-587.}

_{Vries, J.J. de (2004). From speculation to science: The founding of groundwater hydrology in the Netherlands. Dutch pioneers of the earth sciences: 139-164, R.P.W. Visser, J.L.R. Touret, eds. Koninklijke Nederlandse Akademie van Wetenschappen: Amsterdam.}