the Howard N. Potts Medal in 1936. In World War II, Vening Meinesz was involved in the Dutch resistance. After the war he could take up his tasks as a professor again. From 1945 to 1951 he was the director of the KNMI. From 1948 to 1951, Vening Meinesz was President of the International Union of Geodesy and Geophysics. He retired in 1957, and died in Amersfoort in 1966. Research and discoveries The vast amounts of data that his expeditions yielded were analyzed and discussed together with other leading Dutch Earth scientists of the time J.H.F. Umbgrove, B.G. Escher and Ph.H. Kuenen, the results were published in 1948. An important result was the discovery of elongated belts of negative gravity anomalies along the oceanic trenches. The mean gravity force appeared to be the same on land and at sea, which was in agreement with the principle of isostasy. Vening Meinesz was especially intrigued by the oceanic trenches. The coexistence of active volcanism, large negative gravity anomalies and the sudden difference in terrain elevation could only be explained by assuming the Earth's crust was somehow pushed together at these places. As a geophysicist, he was prejudiced that the crust was too rigid to deform at that scale in such a way. His discoveries could be explained only with the development of the theory of plate tectonics in the 1950s. Submarine expeditions Vening Meinesz measured the gravity field of the Earth with his pendulum apparatus on board several submarines. The following expeditions are described in his publications, "Gravity Expeditions at Sea" Vol 1: 1923–1930 HNLMS K II (1923) HNLMS K XI (1925) HNLMS K XIII (1926–1927) HNLMS K XIII (1928–1930) Vol II: 1923–1933 HNLMS O 13 (1932) Vol III: 1934–1939 HNLMS K XVIII (1934–1935) HNLMS O 16 (1937) HNLMS O 12 (1937) HNLMS O 13 (1938) HNLMS O 19 (1939) Vening Meinesz was not on board during expeditions after 1939. His experiments were performed by his students. Vol V: 1948–1958 HNLMS O 24 (1948 - 1949) HNLMS Tijgerhaai (1951) HNLMS Walrus (1957) HNLMS Vos (1955) HNLMS Zeeleeuw (1956) HNLMS Fret (1957) Legacy Named after him are: a gravimeter, an apparatus to measure gravity a mathematical function used in geodesy a medal of the European Geophysical Society/European Geosciences Union a research school at Utrecht University the crater Vening Meinesz on the Moon. See also List of geophysicists References Bibliography External links Vening Meinesz