In 1766 the Royal Society engaged James Cook to travel to the Pacific Ocean to observe and record the transit of Venus across the Sun. The expedition sailed from England on 26 August 1768, rounded Cape Horn and continued westward across the Pacific to arrive at Tahiti on 13 April 1769, where the observations of the Venus Transit were made. Once the observations were completed, Cook opened the sealed orders which were additional instructions from the Admiralty for the second part of his voyage: to search the south Pacific for signs of the postulated rich southern continent of "Terra Australis".