.Map showing global visibility of the transit of Venus, 1761. From James Ferguson, Astronomy explained upon Sir Isaac Newtons Principles, and made easy to those who have not studied Mathematics. To which are added, a Plain Method of finding the Distances of all the Planets from the Sun, by the Transit of Venus over the Suns Disc, in the Year 1761. An Account of Mr. Horroxs Observation of the Transit of Venus in the Year 1639: and, of the Distances of all the Planets from the Sun, as deduced from Observations of the Transit in the Year 1761, 10th ed. (London, 1799), pl. XVII.