About book Longitude: The True Story Of A Lone Genius Who Solved The Greatest Scientific Problem Of His Time (2005)
Longitude from Dava Sobel is a fascinating account of how a virtually unknown watchmaker named John Harrison conquered one of the oldest and thorniest problems surrounding the ocean voyages - the problem of accurately measuring longitude -, which stumped even the best of scientific minds for centuries. A fascinating problemIt was Ptolemy in ‘Geographia’, written in the 2nd century, who contributed the concept of a co-ordinate system based on the imaginary lines of latitude and longitude, for accurately plotting any spot on the surface of earth. With these imaginary lines he bought a new light in to the maritime explorations and map-making methods of his time. The sailors while at the ocean found it pretty straightforward to find their current latitude - which is drawn parallel to each other while girdling the globe – by measuring the height of the sun or any known celestial bodies. But accurately measuring their current longitude was an entirely different case, as the longitudinal lines loop from the North Pole to the South Pole and back again in great circles, which converge at the ends of the earth. Since it is an angular measurement, which is based on time, the sailors had to have access to two different times - the current time on-board the vessel and the time at a known and pre-selected longitudinal location – at the same instance for calculating the hour differences to work out the geographical separation and the longitude. From a modern viewpoint with our easy-to-carry accurate time-telling devices and instant communication this problem, which a sailor faced in finding the exact time at two different locations, may feel far-fetched. But a sailor in the middle of an ocean pre-dating 18th century only had limited resources in the form of either a pendulum driven clock which was not at all reliable – as the factors like gravity, motion of the vessel, temperature and atmospheric pressure affected the pendulum and there by the time – or by comparing positions of moon or planets like Mars with their anticipatory positions in working out the longitudinal values; both these methods were crude with a high level of inaccuracy.Since the days of Ptolemy, legendary scientific and exploratory minds like Amarigo Vespucci, Sir Issac Newton and Galileo Galilei did a lot of research into this matter but it took sixteen more centuries for mankind to finally invent a reliable solution for this problem.A tragedy & the declaration of a prize moneyIn 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. This disaster and huge protest from the merchants and seamen resulted in the formation of a parliamentary committee for finding a practical solution for the longitude problem. This was followed by the 1714 ‘Longitude Act’ by the parliament, which promised a prize money of £ 20,000 for a suitable solution. Dava Sobel covers this formation of the committee and the announcement of the reward in detail.Sir Issac Newton, who was consulted by the committee, at first suggested the idea of a ‘watch’ for tackling the longitude problem.“One method is by a Watch to keep time exactly. But, by reason of the motion of the Ship, the Variation of Heat and Cold, Wet and Dry, and the Difference of Gravity in different Latitudes, such a watch hath not yet been made.”But he believed that such a watch with too many technical challenges was not going to be a reality and was aligned more towards finding a solution for the longitude problem in the realms of astronomy. “A good watch may serve to keep a reckoning at Sea for some days and to know the time of a celestial Observation; and for this end a good Jewel watch may suffice till a better sort of Watch can be found out. But when the Longitude at sea is once lost, it cannot be found again by any watch.”Newton died in 1727, and therefore did not live to see the predecessor of the modern day chronometers become a reality. At the same time another less known figure; a skilled watchmaker from Lincolnshire named John Harrison who was stimulated by the scientific and the monetary factors surrounding this riddle decided to find a solution of his own. 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. His handmade sea-clocks - which are elaborate pieces of engineering marvels and still in display in working condition at the Royal Observatory, Greenwich, England - gave the world the first reliable method for measuring the longitude.Dava Sobel records the background and each step of this pioneering invention in an easy to read form, by guiding the reader through a tumultuous story of the sheer determination and relentless pursuit for perfection from a self made man and the obstructions, unkempt promises and villainy he had to face from some of his jealous contemporaries. This concise and engaging chronicle of an innovative engineering deed covers a lot of details on the history, science and politics, which led to this invention and is a recommended read for anyone who is interested in maritime history and science. Since I read an updated fully illustrated edition of ‘Longitude’, which was published later, the book was a treasure trove with a large selection of rare photographs - including Harrison's sea-clocks, documents of declarations, letters, scientific articles, maps and diagrams which added greatly to the value of the volume. The illustrated edition is highly recommended.
La Historia está llena de pequeños descubrimientos capaces de cambiar el mundo. Aunque debería decir pequeños vistos desde nuestros días. Este es el caso de la longitud, es decir, esas líneas imaginarias que trazan nuestro planeta desde los polos, dividiéndolo en veinticuatro partes iguales. La longitud era fundamental en tierra firme para trazar mapas lo más exactos posibles, pero sobre todo era esencial para la navegación. El mundo era un gran desconocido cuyos horizontes estaban todavía por descubrir y el único medio para hacerlo era en barco, surcando esos océanos y mares ignotos donde cualquier error de cálculo podía suponer perderse en su inmensidad y morir con seguridad, ya sea por la escasez de agua potable y alimentos como por escorbuto. Un barco podía pensar que estaba arribando a su destino cuando quizás era todo lo contrario, o podía colisionar con elementos desconocidos provocando su hundimiento.Hay que pensar en la longitud como un elemento asociado al tiempo. 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. Por lo tanto es fundamental saber en todo momento el tiempo real tanto en el barco como en el lugar desde el que se ha partido o el de destino. Parece simple, con un simple reloj arreglado. Pero no es tan fácil como parece, porque la temperatura y la presión atmosférica afectan mucho la maquinaria de los relojes, adelantándolos o retrasándolos o simplemente parándolos. El capitán pensaba que estaba a X minutos de su destino y se encontraba con que el tiempo pasaba y no arribaban a lugar alguno. Y aquí entraban en juego los partidarios de los relojes y los que preferían guiarse por el mapa estelar, mirando el cielo.Era tan importante para los países encontrar una solución al problema de la longitud, que les hacía perder barcos, mercancías, hombres y dinero, que decidieron poner una recompensa a aquél que diese una solución lo más exacta posible. El gobierno inglés llegó a ofrecer 20.000 libras, el equivalente a varios millones en la actualidad, estableciéndose así el Decreto de la Longitud de 1714.Muchos científicos de renombre hicieron frente al reto pero sólo uno lo consiguió, John Harrison. Esta es su historia, la de él y la de otros tantos que quisieron encontrar una solución al problema. Galileo, Newton, Huygens y un largo etcétera no fueron capaces que dar con la clave. Tuvo que llegar Harrison, un desconocido, un autodidacta aficionado a los relojes, carpintero de profesión para poner fin al problema. Y no lo tuvo nada fácil, porque además de intentar construir sus máquinas de precisión, tuvo que hacer frente a la oposición de los astrónomos, empeñados en que su método era el mejor y más adecuado.Dava Sobel, periodista científica, nos ofrece un relato claro y apasionante de un descubrimiento que cambió nuestra Historia para siempre. Parece mentira que algo para lo que actualmente son necesarios dos simples relojes de pulsera, trajese de cabeza a medio mundo.
Do You like book Longitude: The True Story Of A Lone Genius Who Solved The Greatest Scientific Problem Of His Time (2005)?
This book was intended for the general reader. 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. Instead it focused on description of John Harrison's quest to build an ocean chronometer. The author treats the difficulties Harrison encountered convincing the Board of Longitude of the efficacy of his devices as a matter of petty politics and egotism without offering the reader suffici
—William T.
To quote an esteemed LC history professor on the technical difficulties of pre-modern navigational technology: "Nowadays, you'd refer to that as being lost. But they actually thought they could get somewhere." Shortly after people discovered that the world was round and wanted to sail around it, they realized that they had no way of telling how far they'd gone and how close they were to where they wanted to be, as opposed to how close they were to the Bermuda Triangle, for example, or the giant pointy sneak-attack rocks that were about to sink their ship. The kingdoms of Enlightenment Europe were basically racing against each other to find a way to calculate longitude that worked better than eyeballing the north star with a sextant on a pitching deck, which pretty much didn't work at all. Longitude is the story of John Harrison, the man who invented the first clock accurate enough to keep time at sea, allowing navigators to know exactly where they were on an East-West scale. Harrison, and the reader, get sucked into a whirlpool of royal and scientific politics, which can get very dirty. Also has a cameo appearance by everyone's favorite benignly insane monarch, George III.
—Emily
This little book tells the story of how inventors attempted to solve the vexing problem of obtaining a critical part in calculating longitude -- having a reliable timepiece providing accurate, standardized time on the sea. It's a surprisingly exciting tale: there was a contest, a rich reward and a deadline for entries. Before this problem was solved, sailors could calculate latitude by the stars but longitude required consistent, reliable timekeeping in all ocean conditions from one fixed point. Even with no penchant for science, I found this fascinating, esp. after visiting Greenwich, England, the museum and the very spot to which world time is related (as in Greenwich Mean Time). The author explains all the challenges involved and has written a suspenseful, interesting book about a subject I took for granted.
—Miranda Davis
