The subtitle here tells the reader exactly what the book is about; what it doesn't say is how much fun it is to read. The Greek astronomers could measure latitude as early as the third century b.c., but more than 2,000 years passed before the development of a reliable method for measuring longitude. Former New York Times reporter Sobel (coauthor, Arthritis: What Works, 1989, etc.) sets the stage by recounting the difficulties early navigators had in determining their exact longitude. After the loss of many ships and human lives as a result of navigational errors, in 1714 Parliament offered a rich prize for a practical way to measure longitude at sea. British astronomers saw a solution in the stars, by making sufficiently accurate measurements of lunar positions and comparing them to positions calculated for a known reference point. But the calculations could take hours and were tricky even in the best of circumstances; one future astronomer royal, under pressure, botched a measurement of the longitude of Barbados. Enter John Harrison, an apparently self-taught English clockmaker. Over a period of 40 years, he developed four increasingly precise chronometers capable of holding accurate time over a long, rough sea voyage. Comparing the chronometer's time to local sun time, a navigator could measure longitude with high precision in short order. Despite fierce opposition from astronomers (who scorned a "mere mechanic"), Harrison's clocks were enthusiastically endorsed by every mariner who put them to the test (including such luminaries as Cook and Bligh). With the support of King George III, the clockmaker eventually prevailed and won the prize. Sobel tells his story (and the larger history of the search for longitude) clearly, entertainingly, and with a fine sense of the era in which it took place. Breezily written and full of fascinating characters and facts, here's a science book as enjoyable as any novel.
Dava Sobel Longitude Pdf 14
At 8.00pm on the 22nd of October 1707, the Association, flagship of the Royal Navy, struck rocks off the Scilly Isles with the loss of the entire crew. Throughout the rest of the evening the remaining three ships in the fleet suffered the same fate. Only 26 of the original 1,647 crew members survived. This disaster was a direct result of an inability to calculate longitude, the most pressing scientific problem of the time. It pushed the longitude question to the forefront of the national consciousness and precipitated the Longitude Act. Parliament funded a prize of ?20,000 to anyone whose method or device would solve the dilemma. For carpenter and self-taught clockmaker John Harrison, this was the beginning of a 40 year obsession. To calculate longitude it is necessary to know the time aboard ship and at the home port or place of known longitude, at precisely the same moment. Harrison's dream was to build a clock so accurate that this calculation could be made, an audacious feat of engineering. This work reflects on aspects of this epic tale, brilliantly brought to life in Dava Sobel's book Longitude. Much of the music is mechanistic in tone and is constructed along precise mathematical and metrical lines. The heart of the work however is human - the attraction of the ?20,000 prize is often cited as Harrison's motivation. However, the realisation that countless lives depended on a solution was one which haunted Harrison. The emotional core of the music reflects on this, and in particular the evening of 22ndOctober 1707. Peter GrahamCheshireJuly 2000 2ff7e9595c
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