Mercury (planet) at a steep angle. Mercury is 10° above the horizon when the planet appears directly above the Sun (i.e. its orbit appears vertical) and is at maximum elongation from the Sun (28°) and also when the Sun is 18° below the horizon, so the sky is just completely dark. This angle is the maximum altitude at which Mercury is visible in a completely dark sky. At middle latitudes, Mercury is more often and easily visible from the Southern Hemisphere than from the Northern. This is because Mercury's maximum western elongation occurs only during early autumn in the Southern Hemisphere, whereas
The empire on which the sun never sets as "Christopher North" in "Blackwood's Magazine" in 1829, is sometimes credited as originating the usage. However, George Macartney wrote in 1773, in the wake of the territorial expansion that followed Britain's victory in the Seven Years' War, of "this vast empire on which the sun never sets, and whose bounds nature has not yet ascertained." In a speech on 31 July 1827, Rev. R. P. Buddicom said, "It had been said that the sun never set on the British flag; it was certainly an old saying, about the time of Richard the Second, and was not so applicable then as