Nautical mile 1 sea mile", followed by "For most practical purposes distance is measured from the latitude scale, assuming that one minute of latitude equals one nautical mile". One tenth of a nautical mile is a cable length. The derived unit of speed is the knot, defined as one nautical mile per hour. The metre was originally defined as of the meridian arc from the North pole to the equator passing through Dunkirk. The Earth’s circumference is therefore approximately 40,000 km. The equatorial circumference is slightly longer than the polar circumference – the measurement based on this (40,075.017 km x x =
Nautical fiction importance of naval power in maintaining Britains' vast worldwide empire led to numerous novels with nautical themes. Some of these just touch on the sea, as with "Sylvia's Lovers" (1863) by Elizabeth Gaskell, where the nautical world is a foil to the social life ashore. However, British novelists increasingly focused on the sea in the 19th century, particular when they focus on the upper classes. In such works sea voyages became a place for strong social commentary, as, for example Trollope's "John Caldigate" (1877), in which Trollope depicts a character travelling to Australia to make his fortune, and Wilkie Collins's