Anyone alive in the eighteenth century would have known that the longitude problem was the thorniest scientific dilemma of the day and had been for centuries Lacking the ability to measure their longitude, sailors throughout the great ages of exploration had been literally lost at sea as soon as they lost sight of land Thousands of lives, and the increasing fortunes of nations, hung on a resolution.The scientific establishment of Europe from Galileo to Sir Issac Newton had mapped the heavens in both hemispheres in its certain pursuit of a celestial answer In stark contrast, one man, John Harrison, dared to imagine a mechanical solution a clock that would keep precise time at sea, something no clock had ever been able to do on land Longitude is a dramatic human story of an epic scientific quest and Harrison s forty year obsession with building his perfect timekeeper, known today as the chronometer Full of heroism and chicanery, it is also a fascinating brief history of astronomy, navigation, and clock making, and opens a new window on our world.On its 10th anniversary, a gift edition of this classic book, with a forward by one of history s greatest explorers, and eight pages of color illustrations.

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

  1. Peter Peter says:

    I first read Longitude, by Dava Sobel, just after I finished high school, and I devoured it in a sitting or two It was the first non fiction book, I think, that I really couldn t put down The true story is great legendary historical figures like Isaac Newton, Galileo, James Cook, King George III scientific conundrums innovative engineering a ransom of millions at stake and a humble, lone man competing against oppressive and manipulative big wigs.Background Latitude lines are the parallel lines that circle the globe above and below the equator, and any sailor could figure out his latitude by measuring the length of the day or looking at the angle of the sun or the north star But finding one s longitude, the lines that connected the north and south poles, was much difficult Anyone could determine that he was on the tropic of cancer, but determining how far along the tropic of cancer was a different challenge one that, if solved, would revolutionize navigation and save countless lives In 1714, Parliament offered a purse worth 20,000 Pounds millions today to anyone who could solve the longitude problem John Harrison was a quiet, hard working clockmaker who believed he had found the way.Re reading this now, many of the details and events in the story remain as compelling as they were ten years ago Longitude is a tremendous tale of battling scientists and the perseverance of hard work, brilliance, and humility through political intrigue and greed Do I recommend it Yes, to anyone interested in history, science, engineering, geography, politics, astronomy, navigation, clockmaking Would I teach it Not in an English class, but I d refer to it as a great example of science writing Lasting Impression This book keeps a wonderful balance between the personal, scientific, and political elements of the story It s history you can escape into.

  2. Pramod Nair Pramod Nair says:

    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 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 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 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.

  3. Max Max says:

    On October 22, 1707 four English warships crashed into the rocks of the Scilly Isles southwest of England They quickly sank killing 2,000 men The cause of this catastrophe was the inability to determine longitude, a problem that beset mariners everywhere In 1714 the British Parliament set a 20,000 reward for whoever could solve the problem The Board of Longitude, which would be primarily comprised of astronomers, was set up to award the money To win the full prize, the method or device had to be accurate to within one half degree on a trip from England to the West Indies.There had been many ideas about how to determine longitude, but none worked reliably They fell into two basic camps the astronomical and the clock The idea behind astronomy was to find a pattern of stars, the track of the moon or even the eclipses of the four known moons of Jupiter that would yield longitude The clock idea was based on time difference 15 degrees of longitude equals an hour So a clock that could keep accurate time set to London time could be compared with a clock set to local time The local time could be determined by sighting the sun at noon The time difference would give the degrees of longitude from London But prior to the eighteenth century clocks didn t work reliably in the rough environment of ships at sea, so the London clock would be off In 1727, a self educated village carpenter and clock maker, John Harrison, heard about the prize In 1730 he had plans for a chronometer as mariner s clocks of sufficient accuracy would later be called He showed his plans to Edmund Halley of comet fame, a board member, who sent him to a prominent clockmaker and fellow Royal Society member who encouraged Harrison to build his clock Five years later Harrison presented the clock to the board He had been able to take it on a voyage to Lisbon where it proved its worth Harrison s clock was original, intricate and exquisitely crafted The board was impressed but Harrison himself was not He felt he could do better and took another five years to build a second chronometer 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.In the thirty years Harrison was building his three clocks astronomers were busily cataloging stars and navigational instruments were vastly improving By 1760 the board was considering a complicated but effective method of calculating a ship s longitude from the positions of the moon and stars And since the board was mostly made up of astronomers, they instinctively preferred an astronomical solution to a simply mechanical one.Harrison was awarded the prestigious Copley Gold Medal in 1749 at the recommendation of the Royal Society for the many innovations he had made in his clocks that made them so accurate and reliable But as usual Harrison himself was the hardest to satisfy Immediately after completing clock three he built a fourth, a pocket watch that ultimately would win the coveted prize On a West Indies trip the pocket chronometer worked perfectly, but the astronomers on the board dawdled about awarding the prize since they were now enad with an astronomical solution Since presenting his first chronometer, Harrison had been receiving stipends so that his work could continue, but the prize was elusive Harrison felt his chief nemesis was Astronomer Royal, Nevil Maskelyne, a strong advocate of the astronomical method Maskelyne took it upon himself to conduct further tests on Harrison s watch Finally in 1765 the board awarded Harrison 10,000, half the prize, and ordered him to make two of the watches to show it could be duplicated The board also commissioned another clockmaker to build an identical twin of Harrison s watch The twin was selected to accompany Captain Cook on his second voyage around the world The chronometer won high praise from Cook who used it to make accurate maps Finally through the intervention of King George III, Harrison received a final 8,750 in 1773.One of the biggest problems with Harrison s chronometer was the cost, at least 400 to duplicate when a sextant and tables cost 20 But fifteen years later the price would drop to 80 and would keep declining By 1815 over 5,000 chronometers were in service The problem of longitude had been solved Sobel s short history reads quickly The book contains nice photographs of Harrison s clocks showing their complex inner workings The chronometers have been restored and now reside in British museums Sobel explains some of the principles of clock mechanisms and details some of Harrison s innovations She also covers failed as well as successful astronomical approaches to finding longitude But this is also a human interest story of an odd difficult man, a homespun insular genius, who faces the complex scientific society of eighteenth century England Recommended for the science buff and general reader alike.

  4. Claudia Claudia says:

    Really lovely and very interesting reading Everybody knows about longitude but I guess not so many know the struggles and fights behind the tries to conquer it, including myself.John Harrison was a genius of his times beside the fact that he produced the first accurate marine watches for calculating longitude, his pieces are works of art H1 H3 And the masterpiece, H4, completed in 1759 The book is written on everyone s understanding, full of new historical facts for me It was a pleasure and it takes just a few hours to get it done totally worthy of your time.

  5. Mahlon Mahlon says:

    In Longitude, Dava Sobel chronicles the world s quest to tame time In 1714, the English Parliament passed the longitude act It established the Board of Longitude and offered a prize of 20,000 pounds to anyone who could find a simple and practical method for the precise determination of a ship s longitude In particular Sobel highlights John Harrison s pursuit of the prize She traces the arc of his career, and details the innovations of each of his subsequent entries H1 H5 Unfortunately, even though his Chronometers repeatedly proved their worth in Sea trial after sea trial, and the watch quickly gained adherents among sea captains, Harrison was thwarted at every turn in his attempt to claim the prize Jealous rivals on the board used their influence to change the rules of the contest multiple times His relations with the board became so acrimonious that eventually his friends went over the board s head and appealed directly to the King himself George III asked that a special act of Parliament be passed and Harrison finally received his prize.Despite it s brevity, Longitude is an incredibly engaging and educational book Sobel writes in a way that makes the science and math accessible to the general reader.If you re interested in this subject I d also recommend the 2000 AE movie, which was based on this book.

  6. John John says:

    An amazing book following the attempts to solve the longitudinal navigation problems The author s research covered several hundred years of partial success and many failures Especially interesting was the English contest for solving the problem An amazing man, John Harrison, worked tirelessly to conquer the problem The trials of Harrison, and the jealously of others in his attempts made for a good story. This genius is credited with producing the first marine machine to accurately calculate longitude Then he reduced his machine to a marine watch He made numerous chronometers and many of them may be seen in the Royal Observatory and other places in England.Well written and documented with bibliography.

  7. William T. William T. says:

    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 sufficient detail about the technical disputes to make any judgments about the scientific debate at the center of the controversy.This book was a bit of a disappointment considering the glowing reviews it received.

  8. Jan-Maat Jan-Maat says:

    Interesting story Reasonably written Possibly a model for a certain kind of non fiction book, the type with very long sub titles that are meant to cast light on a very short main title, the whole presumably being the original elevator pitch that the author made to the publisher This one is all about the late 18th century watch maker, John Harrison, who builds a series of highly accurate watches in an attempt to win a prize for a device to be able to establish longitude at sea Nice, does what it says on the tin type book In the tradition of praising people whose work made it possible to do things a little better in this case navigate across seas using a map.

  9. Kathleen Kathleen says:

    The British Parliament, in its famed Longitude Act of 1714, set the highest bounty of all, naming a prize equal to a king s ransom several million dollars in today s currency for a Practicable and Useful means of determining longitude I read this historical and biographical account in one evening It s not without flaws, but I was fascinated and gave it 5 stars for holding my attention in a topic I rarely read about, where science, math, politics, and culture intersect with astronomical and nautical history The technical details may be insufficient for some readers, but there was just enough for me Author Dava Sobel caught my interest and held it Kudos to her Anyway.Naval ships were crashing against rocks and smashing to bits, off course because finding longitude was rather a guessing game, even though latitude was fairly straightforward Skippers didn t know how far north or south of their latitudinal orientation they had sailed They d run aground in the dark, the fog, etc So In 1714, King George and Parliament earmarked a HUGE reward 20,000 pounds for whoever was first to come up with a highly reliable way to find longitudinal orientation Solving the longitude problem became a national pastime, for decades All kinds of quacks tried all sorts of crackpot methods Funny funny stuff Sensible seamen, scientists, astronomers, and mathematicians also joined the race However, it was a lowly clockmaker who came up with the best method An enduring method It became his life s work.Did John Harrison actually win the prize, or did jealous prigs and political big wigs cheat him of his due reward Read it yourself to find out It s less than 200 pages.

  10. Clif Hostetler Clif Hostetler says:

    I was reminded of this book today because in was on the PageADay Book Lover s Calendar for 3 31 2015 I read it back in the year 2000 I have favorable recollections of the book, and I found it to be in interesting story The following short review is copied from the calendar.Anyone with an interest in history or things maritime should consider Longitude, said USA Today of this bestseller Sobel describes 18th century clockmaker John Harrison s struggle to invent an accurate chronometer, which measured time, necessary to calculate longitude while at sea Requiring decades of painstaking research, Harrison finally accomplished his goal, but then faded into the mists of time until his reputation was revived by Sobel s book, which is full of little known facts about science, ships, and England in the 1700s LONGITUDE, THE TRUE STORY OF A LONE GENIUS WHO SOLVED THE GREATEST SCIENTIFIC PROBLEM OF HIS TIME, by Dava Sobel 1995 Walker Company, 2007 The link below is to an excerpt from the book