Page:Astronomy for Everybody.djvu/200

The interest which has attached to these transits during the past century arose from the fact that they were supposed to afford the best method of determining the distance of the sun from the earth. This fact and the rarity of the phenomenon led to the last four transits being observed on a large scale. In 1761, and again in 1769, the leading maritime nations sent observers to various parts of the world to note the exact time at which the planet entered upon and left the sun's disk. In 1874 and 1882, expeditions were fitted up on a large scale by the United States, Great Britain, France, and Germany. On the first of these occasions American parties occupied stations in China, Japan, and eastern Siberia on the north, and in Australia, New Zealand, Chatham Island, and Kerguelen Island in the south. In 1882 it was not necessary to send out so many expeditions, because the transit was visible in this country. In the southern hemisphere stations were occupied at the Cape of Good Hope and other points. The observations made by these expeditions proved of great value in determining the future motions of Venus, but it was found that other methods of determining the distance of the sun would lead to a more certain result.