Corvinus University of Budapest, Budapest, Fővám tér 8, 1093 Hungary
Eötvös entered the University of Budapest in 1865 as a law student but, already interested in the mathematical and physical sciences, took private lessons in mathematics from Otto Petzval.
In 1867 Eötvös abandoned the study of law and entered the University of Heidelberg. His studies included mathematics, physics, and chemistry, taught there by such outstanding teachers as Kirchhoff, Helmholtz, and Bunsen. He obtained his doctorate summa cum laude in the summer of 1870.
Gallery of Roland Eötvös
Eötvös went to the University of Königsberg but found the lectures of the theoretical physicist Franz Neumann and of the mathematician Friedrich Richelot less to his taste.
Career
Achievements
The Eötvös crater on the moon was named after Roland Eötvös.
Membership
Hungarian Academy of Sciences
1873
Hungarian Academy of Sciences, Budapest, Széchenyi István tér 9, 1051 Hungary
Eötvös became a corresponding member of the Hungarian Academy of Sciences in 1873 and a full member ten years later; in 1889 he was elected its president. Although the usual term for the presidency was three years, he was reelected until his resignation in 1905.
Hungarian Academy of Sciences, Budapest, Széchenyi István tér 9, 1051 Hungary
Eötvös became a corresponding member of the Hungarian Academy of Sciences in 1873 and a full member ten years later; in 1889 he was elected its president. Although the usual term for the presidency was three years, he was reelected until his resignation in 1905.
Corvinus University of Budapest, Budapest, Fővám tér 8, 1093 Hungary
Eötvös entered the University of Budapest in 1865 as a law student but, already interested in the mathematical and physical sciences, took private lessons in mathematics from Otto Petzval.
In 1867 Eötvös abandoned the study of law and entered the University of Heidelberg. His studies included mathematics, physics, and chemistry, taught there by such outstanding teachers as Kirchhoff, Helmholtz, and Bunsen. He obtained his doctorate summa cum laude in the summer of 1870.
Eötvös went to the University of Königsberg but found the lectures of the theoretical physicist Franz Neumann and of the mathematician Friedrich Richelot less to his taste.
Roland Eötvös was a Hungarian university professor and physicist. He introduced the concept of molecular surface tension, and his study of the Earth’s gravitational field resulted in proof that inertial mass and gravitational mass are equivalent, later a major principle of Albert Einstein’s general theory of relativity.
Background
Roland Eötvös was born on July 27, 1848 in Budapest, Hungary. He was the scion of an aristocratic and intellectual family. His father, Joseph, Baron Eötvös of Vasärosnameny, at the time of Roland’s birth held the portfolio of public instruction and religious affairs in the first, short-lived, responsible Hungarian cabinet; his mother was the former Agnes Rosty. His uncle, Pál Rosty de Barkócz, was a Hungarian nobleman, photographer, explorer, who visited Texas, New Mexico, Mexico, Cuba and Venezuela between 1857 and 1859. The family had a long background of public service, but its intellectual tendencies came to full bloom only in his father, who became Hungary’s foremost writer and political philosopher of the nineteenth century. Young Eötvös thus grew up in an environment leading more or less toward a study of law and government.
Education
Eötvös entered the University of Budapest in 1865 as a law student but, already interested in the mathematical and physical sciences, took private lessons in mathematics from Otto Petzval.
At his father’s request Joseph Krenner, the future professor of mineralogy at the university, introduced Eötvös to the study of physical sciences; at the same time he worked in the chemistry laboratory of Charles Than.
In 1867 Eötvös definitely abandoned the study of law and entered the University of Heidelberg. His studies included mathematics, physics, and chemistry, taught there by such outstanding teachers as Kirchhoff, Helmholtz, and Bunsen. After three semesters he went to the University of Königsberg but found the lectures of the theoretical physicist Franz Neumann and of the mathematician Friedrich Richelot less to his taste. For a while Eötvös toyed with the idea of joining the arctic expedition headed by August Petermann; but he finally decided, on his father’s advice, to return to Heidelberg, where he obtained his doctorate summa cum laude in the summer of 1870.
Apparently the subject of his doctoral thesis was identical with the subjects of three papers published by him in 1871, 1874, and 1875; they dealt with a problem formulated by Fizeau. The question was raised whether the relative motion of a light source, with respect to an immobile ether, can be detected by measuring the light intensities in both the same and the opposite directions of the motion. Eötvös generalized the calculations for both the emitter and the detector being in motion and extended it to astronomical observations. This purely theoretical work became, decades later, the object of many important papers, leading ultimately to the theory of relativity.
His professors profoundly influenced Eötvös’s working habits. Kirchhoff taught him the importance of accuracy in measurements. Helmholtz liked to spend as much time as possible with his students and showed Eötvös the value of individual discussion. His knowledge of theoretical physics, and in particular of potential theory, came from Franz Neumann.
At the end of his studies in 1870, Eötvös returned to Hungary and in 1871 became Privatdozent at the University of Budapest. In 1872 he was promoted to full professor at the same university. At first he taught theoretical physics; in 1874 he added experimental physics to his duties; and in 1878, at the retirement of Ânyos Jedlik, professor of experimental physics, he took over that chair.
His investigations on capillarity were published in a few papers between 1876 and 1886. After 1886 there were no further communications by Eötvös on this subject, although the law of Eötvös attracted wide attention and during the next few decades a considerable number of papers appeared, examining and extending the concepts introduced by him.
After 1886 practically all of Eötvös’s scientific papers concentrated on his lifework: gravitation. He was interested in this subject on and off before then, and there is some evidence of a gradually awakening interest in earlier papers and speeches. The exact year when his interest swung from phenomena involving van der Waals forces to the weakest known forces in the universe cannot be ascertained. A partial motivation may have been a request by the Termeszet-tudomanyi Tarsulat (Hungarian Society for Natural Sciences) in 1881 for the determination of the gravitational acceleration in different parts of Hungary.
His first short Hungarian-language publication on gravitational phenomena appeared in 1888. In January 1889 he presented a short paper to the Hungarian Academy of Sciences concerning his search for a difference in gravitational attraction exerted by the earth on different substances. This short paper, published in 1890, reported that within the accuracy achieved with his torsion balance, all substances investigated experienced the same force of attraction per unit of mass.
From the beginning of his gravitational researches Eotvos concentrated on the use of the instrument he called in a later paper the Coulomb balance, in recognition of the invention and use of torsion balance by Charles Coulomb. The achievements of Eötvös in the use of his instrument are threefold. By developing the complete theory of the Eotvos balance, he was able to push its sensitivity to such a point that it took decades to devise methods for exceeding his precision. It is only proper to mention that the high degree of precision he achieved was not due solely to the design of the instrument but depended also on the unparalleled skill he displayed in using it.
The other two accomplishments encompassed the clear recognition of the very important applications of the balance: geophysical exploration and the equivalence of gravitational and inertial mass. In both cases the recognition was followed by intense work proving his insight.
Between 1888 and 1922 Eötvös, together with his collaborators, published a number of papers on his investigations. These included the theory and design of the instrument and the results of its widespread application in Hungary and abroad.
The second extremely important application of the Eötvös balance involved a redetermination of the rate of gravitational acceleration for different bodies. It had been known from earlier work that all bodies fall with the same acceleration (in a vacuum), but the best previous determinations yielded only a limited accuracy. In response to a prize announcement by the University of Gottingen, Eötvös and his collaborators followed up his early measurements on this subject. The new measurements provided not merely a more accurate proof of a principle believed right until then, but much more: his results, proving that gravitational mass and inertial mass are equivalent, the possible deviation being about five parts in 109, became one of the building stones of the theory of general relativity. The experiment proves the “weak” form of the principle of equivalence, which states that the trajectory of a test particle, under the influence of gravitational fields only, depends only on its initial position and velocity, not on its mass and nature. Later confirmation of his results (during the last fifty years) reduced the possible deviation from perfect equivalence by a factor of 1,000.
Late in life Eôtvos became interested in the variation of the gravitational acceleration caused by the relative motion of a body with respect to the earth. The experimental proof of this effect was the subject of two posthumous papers.
Parallel to the geophysical application of the torsion balance, he pursued an investigation of the magnetic anomalies accompanying the gravitational effects. His interest in magnetism led him to paleomagnetic work on bricks and other ceramic objects that covered a period of about 2,000 years. Another side issue attracting his interest was the shape of the earth.
Achievements
Roland Eötvös is remembered as a prominent physicist, and is known today largely for his work on gravitation and surface tension, and the invention of the torsion pendulum.
Many honors were bestowed upon him, including election to a number of foreign academies, as well as prizes and decorations.
Eötvös Loránd University, the Loránd Eötvös Mathematics Competition, and the Eötvös crater on the moon are named after him.
To honor Eötvös a postage stamp was issued by Hungary on July 1, 1932. Another postage stamp was issued on July 27, 1948 to commemorate the centenary of the birth of the physicist. Hungary issued a postage stamp on January 31, 1991.
Eötvös became a corresponding member of the Hungarian Academy of Sciences in 1873 and a full member ten years later; in 1889 he was elected its president. Although the usual term for the presidency was three years, he was reelected until his resignation in 1905.
In 1885 Eötvös and four friends founded the Hungarian Society for Mathematics. A little later physicists were attracted to the new society. In 1891 the Mathematical and Physical Society was founded, and he was elected its first president, a post he held until his death.
Hungarian Academy of Sciences
,
Hungary
1873
Hungarian Society for Mathematics
,
Hungary
1885
Mathematical and Physical Society
,
Hungary
1891
Personality
Eötvös' main relaxation was mountain climbing. For quite a long time he was well-known as one of Europe’s foremost climbers: a peak in the Dolomites is named for him, and the mountaineering handbooks record a number of “first climbs” he made either alone or with his daughters, who became his steady climbing companions.
Interests
mountain climbing
Connections
In 1876 Eötvös married Gizella Horvâth, the daughter of the minister of justice, Boldizsâr Horvâth. They had two daughters, Ilona and Rolanda.
