Longitude by Dava Sobel Reading: Analyze Main Ideas and Supporting Details by Summarizing
 First edition (Usa) | |
| Author | Dava Sobel |
|---|---|
| Genre | Popular Science |
| Publisher | Walker & Visitor (Us) 4th Estate (United kingdom) |
| Publication date | 1995 |
| Pages | 191 |
| ISBN | 978-0-8027-1529-half-dozen |
| OCLC | 183660066 |
Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Trouble of His Fourth dimension is a best-selling book past Dava Sobel about John Harrison, an 18th-century clockmaker who created the first clock (chronometer) sufficiently accurate to be used to determine longitude at sea—an important evolution in navigation. The book was made into a television series entitled Longitude.[i] In 1998, The Illustrated Longitude was published, supplementing the earlier text with 180 images of characters, events, instruments, maps and publications.
Problem of longitude [edit]
Determining longitude on country was adequately easy compared to the job at sea. A stable surface to piece of work from, known coordinates to refer to, a sheltered surroundings for the unstable chronometers of the day, and the ability to repeat determinations over fourth dimension made for great accurateness.
For computing longitude at bounding main however, early on sea navigators had to rely on expressionless reckoning, or if in sight of land, coastal navigation, which involves triangulating several bearings of the same state feature from different positions. Once out of sight of land, longitude became impossible to calculate, which sometimes led to tragedies in stormy or foggy conditions.
In gild to deal with not existence able to calculate longitude, captains would sail to the known latitude of their destination, and follow the line of abiding latitude home. This was known as running down a westing if westbound, or easting if eastbound. [2] In Farley Mowat's book Westviking, he gives examples from the Norse Sagas of Vikings using this practice to hop reliably from Norway to the Faroes, and then Republic of iceland, and then Greenland, then N America, and so back to Ireland, with very primitive instruments.
Determining latitude was relatively piece of cake in that it could be found from the altitude of the sun at apex with the aid of a table giving the lord's day's declination for the twenty-four hour period. Latitude can too exist determined from dark sightings of Polaris, the northern pole star. Notwithstanding, since Polaris is not precisely at the pole, it can only provide accurate information if the precise time is known or many measurements are fabricated over time, which made developing an authentic chronometer for long body of water voyages fifty-fifty more vital.
Navigating purely by latitude was of course vulnerable if the sun was clouded over at apex, and caused problems as it prevented ships from taking the most direct route, a great circle, or a route with the most favourable winds and currents, extending voyages past days or even weeks. This increased the likelihood of short rations,[iii] scurvy or starvation leading to poor health or even death for members of the crew and resultant chance to the ship.
Errors in navigation also resulted in shipwrecks. Motivated past a number of maritime disasters attributable to serious errors in reckoning position at sea, particularly spectacular disasters such as the Scilly naval disaster of 1707 which took Admiral Sir Cloudesley Shovell and four ships of his fleet, the British government established the Board of Longitude in 1714.
"The Discovery of the Longitude is of such Consequence to Cracking Britain for the safety of the Navy and Merchant Ships as well as for the comeback of Trade that for want thereof many Ships have been retarded in their voyages, and many lost..." and appear the Longitude Prize "for such person or persons every bit shall discover the Longitude."
The prizes were to exist awarded to the first person to demonstrate a practical method for determining the longitude of a ship at sea. Each prize, in increasing amounts, was for solutions of increasing accuracy. These prizes, worth millions of dollars in today's currency, motivated many to search for a solution.
United kingdom was non alone in the want to solve the problem. France's Rex Louis XIV founded the Académie Royale des Sciences in 1666. Information technology was charged with, amid a range of scientific activities, the improvement of maps and sailing charts and advancement of the scientific discipline of navigation. From 1715, the Académie offered one of the 2 Prix Rouillés specifically for navigation.[iv] Spain's Philip Ii offered a prize for the discovery of a solution to the problem of the longitude in 1567; Philip Iii increased the prize in 1598. The netherlands added to the effort with a prize offered in 1636.[5] Navigators and scientists in most European countries were aware of the problem and were involved in finding the solution. Due to the international attempt in solving the problem and the scale of the enterprise, it represents i of the largest scientific endeavours in history.
Knowing longitude [edit]
Equally Dava Sobel explains, "To know one's longitude at sea, ane needs to know what time it is aboard ship and also the fourth dimension at the abode port or some other place of known longitude—at that very aforementioned moment. The two clock times enable the navigator to convert the hour difference into geographical separation. Since the earth takes 24 hours to revolve 360 degrees, one hour marks ane/24 of a revolution or 15 degrees. And so each hr's time difference between the ship and starting signal marks a progress of xv degrees of longitude to the eastward or west.
"Every day at sea, when the navigator resets his ship'due south clock to local noon when the sun reaches its highest point in the heaven, and and then consults the home port clock, every hr's discrepancy betwixt them translates into some other 15 degrees of longitude. One degree of longitude equals four minutes of time the world over, although in terms of distance, one degree shrinks from 60.15 nautical miles or 111 km [Earth's circumference existence 21,653.521 nautical miles, or 24,901.55 statute miles at the Equator], to virtually nothing at the poles.
"Precise knowledge of the hour in two different places at once—a longitude prerequisite so easily accessible today from any pair of inexpensive wristwatches—was utterly unattainable up to and including the era of pendulum clocks. On the deck of a rolling ship such clocks would slow downward, or speed upward, or terminate running altogether. Normal changes of temperature encountered en route from a cold land of origin to a tropical trade zone thinned or thickened a clock'south lubricating oil and made its metal parts expand or contract with as disastrous results. A ascension or autumn in barometer pressure, or the subtle variations in the Earth's gravity from i latitude to another, could besides cause a clock to gain or lose fourth dimension."[6]
Harrison's concluding triumph - the compact chronometer
Before the 18th century, bounding main navigators could not find an accurate way of determining longitude. A practical solution came from a gifted carpenter, John Harrison, who solved one of the most difficult problems of his fourth dimension by creating an authentic chronometer. The best scientists of the time, including Sir Isaac Newton, thought it impossible. Harrison spent 4 decades perfecting a watch that would earn him compensation from Parliament and longitude rewards thanks to the recognition and influence of King George III of Great Great britain.[7]
Recognition [edit]
- British Book of the Year, 1997[ citation needed ]
- Modern Library 100 Best Nonfiction, 26th on the Readers List[viii]
- American University of Arts and Messages Harold D. Vursell Memorial Award, 1999[nine]
- Le Prix Faubert du Coton[ix]
- Il Premio del Mare Circeo[9]
- Imperial Society Prizes for Science Books, 1997 (Shortlisted)[10]
- American Library Association Non-fiction Outstanding Books for the Higher Leap and Lifelong Learners, 1999[xi]
- American Library Association Outstanding Books for the College Jump and Lifelong Learners, Science and Technology, 2004[12]
In recognition for Longitude, Sobel was named as a fellow of the American Geographical Club.[nine]
Picture adaptations [edit]
- Nova Online: Lost at Sea, the Search for Longitude
- Longitude (TV series)
See as well [edit]
- American Practical Navigator
- Cardinal direction
- Geodetic organisation
- Geographic coordinate system
- Geotagging
- Peachy-circle altitude
- History of longitude
- Breadth
- Lunar distance (navigation)
- Prime Meridian
- Sextant
- Globe Geodetic System
- John Harrison
References [edit]
- ^ Longitude wins Bafta hat-trick, BBC, Apr 22, 2001
- ^ Dutton's Navigation and Piloting, twelfth edition. G.D. Dunlap and H.H. Shufeldt, eds. Naval Constitute Press 1972, ISBN 0-87021-163-3
- ^ As food stores ran low, the crew would be put on rations to extend the time with food. This was referred to equally giving the coiffure short rations, short allowance or petty warrant.
- ^ Taylor, E.G.R., The Haven-finding Art: A History of Navigation from Odysseus to Helm Cook, Hollis & Carter, London 1971, ISBN 0-370-01347-6
- ^ Longitude and the Académie Royale
- ^ http://www.sailtexas.com/long.html
- ^ http://www.nobeliefs.com/sobel.htm
- ^ The Modern Library | 100 Best | Nonfiction | Readers Listing
- ^ a b c d Penguin reading Guides | Galileo's Daughter | Dava Sobel Archived January 7, 2009, at the Wayback Motorcar
- ^ Prizes for Science Books previous winners and shortlists - The Prizes - The Royal Social club
- ^ "Non-fiction Outstanding Books for the College Spring Titles". Immature Adult Library Services Association. 15 March 2007. Retrieved 2015-11-01 .
- ^ "Young Developed Library Services Association (YALSA)". Immature Adult Library Services Association. fifteen March 2007. Retrieved 2015-eleven-01 .
External links [edit]
- Booknotes interview with Sobel on Longitude, January 17, 1999.
Source: https://en.wikipedia.org/wiki/Longitude_%28book%29
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