Academic journal article et Cetera

Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time

Academic journal article et Cetera

Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time

Article excerpt

Dava Sobel. Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. Walker: New York, 1995. Lines of latitude stay parallel to each other as they circle the globe from the Equator to the poles in a series of shrinking concentric circles. The meridians of longitude loop from the North Pole to the South and back again in great circles of the same size, so they all converge at the ends of the Earth.

Any competent mariner can approximately gauge his latitude by the length of the day, the height of the sun or known guide stars above the horizon. To measure longitude meridians one needs to know what time it is aboard ship and also the time at the home port or another place of known longitude - at the very same moment. The two clock times enable the navigator to convert the hour difference into a geographical separation (every hours difference equals fifteen degrees of longitude).

Precise knowledge of the hour in two different places was impossible up to and including the era of pendulum clocks. On the deck of a rolling ship such clocks would slow down, speed up or stop running altogether. According to Dava Sobel, "For lack of a practical method of determining longitude, every great captain in the Age of Exploration became lost at sea despite the best available charts and compasses. From Vasco de Gama to Vasco Nunez de Balboa, from Ferdinand Magellan to Sir Francis Drake - they all got where they were going willy-nilly, by forces attributed to good luck or the grace of God. …

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.