An instrument employed by navigators to guide the ship's course at sea. It consists of a circular box, containing a fly or paper card, which represents the horizon, and is suspended by two concentric rings called gimbals. The fly is divided into thirty-two equal parts, by lines drawn from the centre to the circumference, called points or rhumbs; the interval between the points is subdivided into 360 degrees consequently, the distance or angle comprehended between any two rhumbs is equal to 11 degrees and 15 minutes. The four cardinal points lie opposite to each other; the north and south points form top and bottom, leaving the east on the right hand, and the west on the left; the names of all the inferior points are compounded of these according to their situation. This card is attached to a magnetic needle, which, carrying the card round with it, points north, excepting for the local annual variation and the deviation caused by the iron in the ship; the angle which the course makes with that meridian is shown by the lubber's point, a dark line inside the box. (See adjustment of the compass.)