Eötvös, Lóránd Von

(also Roland von Eötvös). Born July 27, 1848, in Budapest; died there Apr. 8, 1919. Hungarian physicist. Member of the Hungarian Academy of Sciences (1883); president of the academy from 1889. Baron. Son of J. Eötvös.

L. von Eötvös studied at the universities of Budapest, Königsberg, and Heidelberg. He graduated from the University of Heidelberg in 1870 and joined the staff of the University of Budapest in 1871. He was named a professor in 1872. Eötvös served as minister of education in Hungary in 1894 and 1895.

In 1886, while studying capillarity, Eötvös defined the dependence of surface tension on temperature. He turned to the study of terrestrial magnetism and gravitation in 1890 and invented a torsion balance that was used in mineral prospecting. Eötvös proved the equality of inertial mass and gravitational mass to an accuracy of ~10^–8. He established that, as a result of the earth’s rotation, the weight of bodies on moving objects depends on the rate and direction of motion; this phenomenon is known as the Eötvös effect. A unit of measurement of gravitational acceleration has been named for Eötvös.