Pat Shingleton for Friday, July 12, 2013

Without charts, the only means to determine a sailor’s or explorer’s location was celestial navigation. As noted in a previous column, the captain’s chart was little more than the ship’s log. On old maps, a circular directional emblem was a “wind rose.” Mariners in Homer’s time identified direction with wind; early cartographers were part artist, part astronomer, combining wind directions into the wind rose. Once nautical charts were initiated in the 14th century, the four primary winds were schematically positioned around a circle that represented the horizon. Always present was the wind rose with a radial set of points, such as a star, directed into each wind position. The rhumb lines radiated from the central point of the rose, connected to each directional point. More Saturday.

Fastcast: Hot, showers.