EOTVOS, ROLAND, BARON VON

( (German), ) born July 27, 1848, Pest, Hung. died April 8, 1919, Budapest Hungarian Lornd, Br Etvs Hungarian physicist who introduced the concept of molecular surface tension. His study of the Earth's gravitational fieldwhich led to his development of the Etvs torsion balance, long unsurpassed in precisionresulted in proof that inertial mass and gravitational mass are equivalent, later a major principle of Albert Einstein's general theory of relativity. Etvs, the son of Baron Jzsef Etvs, was minister of public instruction in the Cabinet of Sandor Wekerle, resigning in 1895 to devote himself to teaching physics at the University of Budapest.