Henricus Jacobus Charles Tendeloo

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Henricus Jacobus Charles Tendeloo (born July 20, 1896 in Tebing Tinggi (Sumatra), † July 6, 1984 in Renkum ) was a Dutch chemist.

Live and act

Henricus Jacobus Charles was the son of Dr. Henricus Johannes Emile Tendeloo (born December 31, 1859 in Amoerang (Indonesia); † May 22, 1903 in Tandjong Poera (Indonesia)) and his wife Jeanne Cornelia Stamm'ler (also: Stamler, * January 1869 in Probolingo; † 31. July 1947 in Oudenrijn). He attended high school in Leiden and began studying natural sciences at Utrecht University in 1916 . After he had passed his candidate exam in 1918, he completed his military service and then became a teacher of math, chemistry and biology at Willem Lodewijk Gymnasium in Groningen . In 1920 Tendeloo continued his studies and became an assistant in organic chemistry to Pieter van Romburgh . After completing his doctorate in 1922, he switched to Hugo Rudolph Kruyt as an assistant in physical chemistry in 1923 . On January 18, 1926, he did his doctorate with the topic Lading en hydratie (German: loading and hydration ) to the doctor of natural sciences, where he examined the influence of different electrolytes on brines .

After receiving his doctorate, Tendeloo worked as a chemist in a glue and gelatine factory in Delft and from 1928 at the Bataafsche Petroleum Maatschappij in Amsterdam . In 1931 he turned back to training and became a lecturer in chemistry at the agricultural college in Wageningen , which he began on February 2 of the same year with the inaugural address Localisaties op grensvlakken (German: Localization at the interfaces ). During that time he was engaged in research on colloid chemistry in the field of agricultural applications, with a focus on ion exchange in the soil and the associated electrical determination methods. So he examined the soil and the milk, paying particular attention to the mechanism of coagulation . Below is the effect of precipitation on the ground, which occurs at certain depths and has been interpreted as flocculation phenomena.

Together with Aale Pasveer (born March 1, 1909 in Middelburg; † October 4, 2001 in Oudewater), the effects of the rennet enzyme on a calcium aerosol were examined viscometrically and determined as colloid- chemical coagulation. In order to understand the complexity of agricultural systems, he turned to studies of the exchange capacity of earth minerals, with the focus here on the titration of humus and humus soils. From 1934 Tendeloo directed his investigations to adsorption electrons , which are used in agricultural chemistry to determine hydrogen and calcium ions. Different materials were used to create the electrons. The studies on glass have the effect of investigating the electron behavior on plant roots. A glass electrode was found which reacted to cations . In addition to publications of these scientific studies, Tendeloo also published textbooks. So in 1944 a textbook on colloid chemistry was created and in 1955 the textbook Grondslagen der psysische chemie (German: Fundamentals of physical chemistry).

His numerous scientific endeavors also resulted in recognition of his work. He was appointed associate professor in 1937, full professor for physical and colloid chemistry in Wageningen in 1945 and knight of the Order of the Dutch Lion in 1937 . However, he had to go through low points in his life. During the German occupation of the Netherlands in World War II, Tendeloo was imprisoned and interned in the camps in Haren and St. Michielsgestel from 1942 to 1943 . After the Second World War he resumed teaching in Wageningen. Tendeloo became director of a research station of the Dutch Organization for Applied Scientific Research (TNO) in Groningen and in 1950/51 he was elected rector of the agricultural educational institution in Wageningen, in which position he laid the foundations for many building projects in the following years. From 1939 he was a member of the Koninklijke Nederlandse Chemische Vereniging (KNCV), whose chairman he became after the Second World War and later an honorary member. In addition to his scientific work, he was also committed to political issues. From 1939 to 1941 he was a city councilor in Wageningen as a member of the Vrijzinnig Democratische Bond and from 1945 in the same function for the Partij van de Arbeid . In 1962 Tendeloo retired from teaching for reasons of age.


Tendeloo was married twice. His first marriage was on October 10, 1926 in Delft with Marie Antoinette Grondhout (born December 8, 1905 in Leiden, † June 16, 1983 in Heerhugowaard). There are two daughters from the marriage. After the divorce of his first marriage on April 27, 1933 in The Hague, he married Annie Josephine de Groof (born April 14, 1899 Hansweert; † December 26, 1988 in Wageningen) on May 22, 1934. The marriage remained childless. The daughters Cornelle Ellen Eugenie Tendeloo (* August 1929) and Henrica Antoinette Tendeloo (* November 1930) are known from his children.

Works (selection)

  • Lading en hydratie. Paris, Amsterdam 1926 ( online )
  • Localisaties op grensvlakken. Veebman, Wageningen 1931
  • Deel en geheel. Wageningen 1937
  • Handleiding for internships in inorganic analysis, physical chemistry and colloid chemistry. Kniphorst, Wageningen 1940; 3rd edition Kniphorst, Wageningen 1945
  • Physical chemistry. 2nd edition Kniphorst, Wageningen 1946
  • De techniek van het verenigingsleven. 2nd edition Nijgh & van Ditmar, Rotterdam 1951
  • Colloid chemistry. Noorduijn, Gorinchem, 1944; 2nd edition Noorduijn, Gorinchem, 1947; 3rd edition Noorduijn, Gorinchem 1952;
  • De steen der wijzen in dze tijd. H. Veenman, Wageningen 1951
  • Basics of physical chemistry. Kniphorst, Wageningen 1955
  • Chromosomes lectures held at the conference on chromosomes, Wageningen, April 16-19, 1956. Tjeenk Eillink, Zwolle 1956
  • Enzymes. Tjeenk Eillink, Zwolle 1959


  • HAM Snelders: Tendeloo, Henricus Jacobus Charles (1896-1984). In: Biographical Woordenboek van Nederland. The Hague 1989, Vol. 3 ( Online )

Web links

  • Tendeloo entry at the Chemie Historische Groep (CHG)