kamal
kah-MAL
An Arab navigation instrument: a small rectangular card held at arm's length on a knotted string, used to measure the altitude of the North Star above the horizon and thereby determine latitude. Each knot corresponds to a known port. The whole Indian Ocean, navigated with a piece of wood and a string.
Etymology
Arabic: kamāl, carrying a double meaning — "perfection" and "guide." Also called khashaba, simply "wood," for the material it was made from. A wooden card and knotted string, held between the teeth to measure the altitude of Polaris. Arab navigators used it in the Indian Ocean from the 9th century; the Portuguese encountered it when Vasco da Gama rounded Africa in 1497. An early step toward quantitative navigation.
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