The ToV occurs when Venus's orbit causes the planet to speed past the slower moving Earth and visibly cross the Sun, partially obscuring it. The ToV occur in pairs that are 8 years apart and tend to be separated in time by just over a century. The first person to predict and observe the ToV was James Horrocks, on Dec. 4, 1639. There were also ToV observed and recorded in 1761, 1769, 1874 and 1882. The 2012 ToV will be visible in the Americas on the evening of June 5, 2012. The next ToV does not occur until 2117. This vol. contains observations of the ToV on 6/3/1769, recorded by David Rittenhouse, who observed the ToV in Norriton, PA; and John Ewing, who observed the ToV on June 3 and the Transit of Mercury on 11/9/1769, in Phila. Illus.
