Mercator's Chart
or PROJEC- TION, a mode of projection or representation of a portion of the surface of the earth on a plane, in which the meridians are represented by equi-distant parallel straight lines, and the parallels of latitude by straight lines perpendicular to them. This chart is particularly adapted to the purposes of navigation, inasmuch as the plot of a ship's course, or a rhumb line between two points upon it, is represented by a straight line. On this account, as well as on account of the facilities which it affords for making calculations necessary in navigation, Mercator's chart is now almost universally adopted for sailing purposes.