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Baron Loránd Ágoston Eötvös


ELKH was named after Baron Loránd Ágoston Eötvös, aka Baron Roland von Eötvös (1848–1919), internationally recognized Hungarian scholar, professor, academician and public figure. He worked as government minister and also as President of the Hungarian Academy of Sciences. Furthermore, he took crucial steps toward the development of education and the management of academic affairs.

Loránd Eötvös invented the Eötvös pendulum, by which the equivalence of gravitational and inertial mass was proved. His exceptionally accurate measurements proved Albert Einstein’s equivalence theory, which was highlighted in Einstein’s personal letter written to Eötvös.

As a result of his research, he set up the Eötvös rule, which describes how the surface tension of a liquid depends on temperature in physical chemistry. The Eötvös effect is witnessed in geophysics during the gravitational measurements of objects moving with respect to Earth. The Eötvös parameter quantifies the deviation from the Universality of Free Fall for test bodies of different composition.

Milestones of Eötvös’ scientific activity

  • 1875–1885 Capillary-related studies: a reflection method for determining the rules of capillarity, Eötvös rule, Eötvös constant
  • 1886–1919 Gravity and geomagnetic studies
  • 1890 “Gravitational attraction of Earth to different materials” (Academy lecture, 20 January)
  • 1891 Curvature and horizontal variometers
  • 1891 First field measurement on Ság Hill, Celldömölk, Hungary
  • 1896 Investigations in gravity and geomagnetism (summary)
  • 1898 Simple gravity variometer (the Balaton torsion balance)
  • 1901 Bifilar gravimeter
  • 1901 and 1903 The first large-scale survey on the ice of Lake Balaton
  • 1909 In relation to his research on proportionality between inertial mass and gravitational mass he wins the Beneke Prize
  • 1915 Design of an experimental tool to demonstrate the Eötvös effect
  • 1916 Field survey at Gbely (Egbell). Birth of hydrocarbon research geophysics

For further details on Loránd Eötvös’s life and work, see Roland Eötvös Commemorative Year 2019