EOTVOS, ROLAND VON, BARON (1848-1919), Hun garian physicist, son of Baron Josef Eotvos, was born in Budapest July 27, 1848. He studied at Budapest and Heidelberg, and in 1872 he was appointed professor of physics in the University of Buda pest. In the following year he was elected member, and in 1889 president, of the Hungarian Academy of Sciences. From he was Minister of Public Instruction. His first scientific studies were connected with capillarity; in 1885 he published the result of these investigations in which he deduced the law connecting the variations of surface tension with temperature. From 1890 on wards he examined the phenomena connected with the problems of gravitation and of terrestrial magnetism. He constructed a number of magnetic instruments. Later he constructed the double armed torsion balance. This so-called Eotvos-balance is an ex tremely delicate instrument for determining the variations of grav ity quickly and accurately ; it became an essential instrument for the location of subterranean materials. In a treatise which won him the Benecke prize from Gottingen university in 1909, Eotvos demonstrated with great exactitude that the attraction of bodies is independent of the quality of the substance. Towards the end of his life he studied the variations of the gravitation (q.v.) of bodies moving on the earth. He demonstrated by experi ments that if a body moves towards the east it loses in weight. Eotvos showed the rotation of the earth by means of a slowly rota ting gravity balance. He died in Budapest on April 8, 1919.