wallal, western australia was the chosen location for a visiting us lick observatory party of astronomers, led by w. w. campbell, to view the upcoming solar eclipse of 21 september 1922. the purpose of the expedition to view stellar transits of the sun's disk during the eclipse to measure and verify albert einstein's theory of relativity. wallal was preferred for its isolation from man-made light sources, its propensity for clear skies and its location to gain the longest eclipse duration.