"English expedition" . . . . "astronomical observation" . "experimentally verified" . "solar eclipse expedition" . . "an expedition" . "1919 Eddington eclipse expedition" . . "two expeditions" . "Eddington's expedition" . "Eddington's eclipse observations" . . "observations" . "Eddington experiment" . "is tested" . "observations made during a 1919 solar eclipse" . "observation" . . . "Eddington experiment" . . .