Nautical chart always true north, rather than magnetic north, towards which a compass points. Most charts include a compass rose depicting the variation between magnetic and true north. However, the use of the Mercator projection is not without its drawbacks. Mercator's technique was to make the lines of longitude parallel. On the real globe, the lines of longitude converge as one goes north or south away from the equator, until they meet at the pole. This distortion means that horizontal distances are exaggerated. Mercator's solution, imperfect as it might be, was to increase the distance between lines of latitude in proportion; in
How Many Miles to Babylon? good and your spurs be bright. How mony men have ye? Mae nor ye daur come and see.</poem> Various places have replaced Babylon in the rhyme, including London town, Barberry and Berry Bright. The rhyme was not recorded until the nineteenth century, but the reference to Cantelon in the Scottish version has led some to conclude that it refers to Caledon in the time of the Crusades. Babylon may be a corruption of 'Babyland', but the city was a common allusion particularly in seventeenth-century England and 'Can I get there by candlelight?' was a common saying in the sixteenth century.