Mercury (planet) diagram on the right illustrates the effects of the eccentricity, showing Mercury's orbit overlaid with a circular orbit having the same semi-major axis. Mercury's higher velocity when it is near perihelion is clear from the greater distance it covers in each 5-day interval. In the diagram the varying distance of Mercury to the Sun is represented by the size of the planet, which is inversely proportional to Mercury's distance from the Sun. This varying distance to the Sun leads to Mercury's surface being flexed by tidal bulges raised by the Sun that are about 17 times stronger than the Moon's
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