Navigational quadrant. 16th-century illustration of a quadrant used to measure angles and used in geography, astronomy and navigation. The sectors are labelled with 90 degrees, which here is the latitude on the Earth or celestial sphere. The Latin labels refer to the equator (left), the quadrant sights (right) and the plumb-line (lower centre). Diagram from 'Cosmographiae introductio' (1507), printed to accompany the globe and world map produced by German cartographer Martin Waldseemuller (c.1470-1520). They contained the first use of the name America to refer to the New World, honouring the supposed discoverer of the continent, Amerigo Vespucci.