Three fundamental papers of Loránd Eötvös [antikvár]

FOREWORD Loránd Eötvös, one of the most prominent Hungarian scientists, was born on 27th July 1848. Within the confines of this brief Foreword it would be extremely difficult to do full justice to the range and depth of his multifarious activities. After his early work in which he dealt with capillarity and which led to the establishment of the 'Eötvös law', his attention turned to gravitation. His investigations in the latter field proved to be of fundamen- tal importance to the physical sciences. With his invention of the torsion balance, the foundation of applied geophysics was established accompanied by the era of oil exploration utilizing instruments. In fact, Eötvös' ingenious instrument heralded a major breakthrough in prospecting for oil resulting in a great number of oil fields throughout the world being discovered in the 1920s and 1930s. His experimental observations on the principle of equivalence fur- nished evidence for Einstein's general theory of relativity. The results of his experiments obtained at the beginning of the 20th century are still of interest to the physicists of today and they have been used in formulating the hypothesis of the fifth force. One of his discoveries, known as the Eötvös effect, plays an important role in the correction of gravity measurements on moving vehicles. Accurate determination of the velocity and azimuth of moving platforms necessary for the Eötvös correction is still a basic problem of gravity measurements on ships and aircraft. It might be appropriate here to reiterate the view that a surprising number of people seem to be unaware of the extent of Eötvös' achievements. Since his death, the Eötvös Loránd Geophysical Institute (ELGI) does its best to maintain the tradition of his intellectual heritage and acts as custodian of his original instruments and documents. On the 150th anniver- sary of his birth ELGI wishes to highlight the achievements of Loránd Eötvös by publishing a short biography and facsimiles of three fundamental papers together with their English translations to make them accessible to a wider readership.