Longitude

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The focus then shifts to a biography of John Harrison, the 18th century clockmaker who attempted to solve this problem based on timekeeping. As I turned the pages, I marveled at the intricacies of clockmaking and the profound impact Harrison's chronometers had on navigation. I’m not sure how to describe how lost you could be, out there on the ocean, no longer in sight of shore. Without Harrison and his chronometers, Great Britain would not have had the success it did in establishing and maintaining its empire, making one British astronomer’s personal vendetta against Harrison and his chronometers all the more damning. The earth’s rotation makes the heavens generally useless, and with no landmarks out at sea, one was essentially sailing blind.

Si tenemos en cuenta que circunvalar la Tierra supone 360º, que se dividen en 24 meridianos de longitud, obtenemos una separación entre ellos de 15º, calculándose cada grado en minutos. Indeed, echoes of the great rivalries across the ages surface in Longitude, reminding us that science is never as simple nor as objective as we like to think. If enough signal boats, therefore, were stationed at strategic points from sea to sea, sailors could gauge their distance from these stationary gun ships by comparing the known time of the expected signal to the actual shipboard time when the signal was heard. In 1707, a British fleet of vessels under Admiral Sir Clowdesley Shovell met with a tragic disaster as the result of miscalculations in their whereabouts leading to the sinking of four warships with a death toll of more than 1600 mariners.Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time is a 1995 best-selling book by 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 development in navigation. It is utterly fascinating to read about the extend of human inginuity, but also entertaing to see some of the hair-brained alternative schemes that were considered to addresz this problem.

Consequently it did not deal much with the details either of the astronomical or mechanical approaches to solving the problem of finding longitude on the high seas. A practical solution came from a gifted carpenter, John Harrison, who solved one of the most difficult problems of his time by creating an accurate chronometer. But the episodic nature of the chapters, and the abbreviated way she communicates the stories of the testing of H–3, H–4, etc. For centuries, thinkers have understood that the answer was measuring time, and eventually two possible solutions emerged.Possessed with a brilliant mind he succeeded initially in creating a prototype and then further versions of perfect working models of the world’s first marine-chronometers thereby revolutionizing the ocean travels.

Latitude corresponds both to the sun’s altitude in the sky (at noon) and to the altitude of certain stars (if you are in the Northern Hemisphere, Polaris is a good choice) at night. The trick to making any historical account interesting lies in exposing the details and connections that a casual reader, like myself, wouldn’t necessarily know. Other less elegant or accurate solutions to the longitude problem became mere footnotes in Harrison’s journey, as did Neville Maskelyne.The first several chapters describe the difficulties encountered by ships attempting to navigate solely based on latitude. The Illustrated Longitude,The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dava Sobel and William J. Y aquí entraban en juego los partidarios de los relojes y los que preferían guiarse por el mapa estelar, mirando el cielo.

With these imaginary lines he bought a new light in to the maritime explorations and map-making methods of his time. Lavishly produced with over 200 illustrations, The Illustrated Longitude has much new material to help the reader learn more of John Harrison’s extraordinary story and his times.The Royal Observatory in Greenwich played a significant role in the story, as did the scientific establishment's skepticism of Harrison's unconventional methods. The Royal Society tested the second clock and gave it accolades but Harrison again decided he could do even better and took twenty years to build a third. It’s a book about ingenuity, dedication, betrayal, eventual triumph, and a great deal of hard-earned money. In the thirty years Harrison was building his three clocks astronomers were busily cataloging stars and navigational instruments were vastly improving.