Expeditions for the observation in Sobral, Brazil, of the May 29, 1919 total solar eclipse

Abstract

I report on the three expeditions organized to observe, in the Brazilian State of Ceará, the total solar eclipse on May 29, 1919. Apart from the well-known British expedition, which aimed to perform measurements of the bending of stellar light rays passing near the Sun, resulting in the confirmation of Einstein’s Theory of General Relativity, there were two other expeditions in that occasion. One has been a Brazilian expedition, organized by the National Observatory, with the aim of studying the solar corona. The other has been a North-American expedition, organized by the Carnegie Institution, aiming to perform measurements related to terrestrial magnetism and atmospheric electricity.