1To Benjamin Franklin from John Winthrop: On Observing the Transit of Venus, 6 September 1769 (Franklin Papers)
AL (extract): The Royal Society The observations of the transit of Venus in 1761 had not fulfilled the widespread hope of establishing the solar parallax, and thereby the mean distance between the earth and the sun. The hope grew, however, as scientists of many countries prepared to improve and expand their observations of the transit of June, 1769. Although John Winthrop was no longer well...