British Preparations for Observing the Transit of Venus of 1761

Abstract

WO important astronomical events that aroused the educated world and resulted in the greatest co-operative enterprises in the history of science to that time took place during the latter half of the eighteenth century. The preparations for the observations were accompanied by considerable excitement, for the transits of Venus in I76i and I769, properly observed from various points on the earth's surface, would enable astronomers to determine the solar parallax and thereby obtain the distance between the earth and the sun. Once this was accomplished, other distances in the solar system then known only relative to one another could be computed, and the Newtonian system of the world could be brought closer to completion by the determination of its exact scalar dimensions.' For the historian of science, the attempted determination of those dimensions in I76i is truly important. In a broader sense, however, the preparations for the large-scale international effort to view the transit throw some light on the relations between science and society in the Age of Reason. On either side of the Atlantic the British world combined private and public funds and institutions in what proved, in both cases, to be a prelude to more successful observations in I769. The very idea that the transits of the planet Venus might serve as a natural astronomical instrument for determining the size of the universe was due to Edmund Halley.2 But for a long time following the announce-