Longitude : The True Story of the Lone Genius Who Solved the Greatest Scientific Problem of His Time

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Summary: Great story, but BEWARE of inaccuracies in this book
Review: John Harrison completes his first pendulum clock in 1713 before the age of 20. He made the gears for this out of wood which was radical for such a use, but as a carpenter, perhaps not to him---which is a mark of genius, I'd say; to reach beyond accepted norms in this manner. This he did after borrowing a book on math and the laws of motion; which he copied word for word, making his own copy. He incorporated different varieties of wood into his clock for strenth and later invented a bi-metal pendulum to counteract the expansion and compression of various individual metals. He also employed friction-free movements so as to do away with problematic lubricants. When intrigued by the puzzle of time at sea and the issue of longitude he contemplated substituting something not prone to gravity, as a pendulum of course is, to track times passing. In 1737 he creates a cantilevered clock 4 foot square. The "Longitude board" (which had offered a cash bonus to anyone who could devise a method in which time at sea could be kept) admired this prototype. Four years later he returns with an improved model; then starts on a 3rd model, like the previous two, also a fairly large sized clock. But there exists a problem within this book: An artisan freemason by the name of John Jefferys at the Worshipful Company of clockmakers befriends Harrison and then later presents to him a pocket watch in 1753. Then in 1755, while still working on his 3rd model, Harrison says this to the Longitude board: I have..."good reason to think" on the basis of a watch "already executed that such small machines[he's referring to pocketwatches] may be of great service with respect to longitude." He then completes version 3 in 1759. His fourth version appears just a year later, however, and is a 5 inch wide pocketwatch! The obvious inference made by the author is that after he received the pocketwatch from Jeffreys he seemingly put his version #3 on the backburner and soon started on the pocketwatch 4th version. The author does not claim Harrison copied anything from the Jeffreys model, but she certainly phrases this section so as to lend one to believe that this may have been the case; that Jefferys had a hand in the masterstroke invention Harrison eventually produced in version #4. This is not true. Harrison commissioned the watch he received from Jeffreys and was based on Harrison's specifications. It seems that Harrison simply asked Jeffreys to test an idea which he himself hadn't the time to attack just then; as he was still working on his 3rd version of a table-top prototype clock. Hence Harrison's above statement to the board in 1755 whence his ideas were validated by Jeffreys. In addition, the author plays up the part of the Astronomer Royal's part in attempting to impede Harrison from convincing the longitiude board of the efficacy of a time-piece solution to this problem over a celestial answer to this conundrum. The author also jazzes up the issue of whether Harrison received the prize the board promised to pay for a successful solution herein; even though the board supported him for upwards of 20 years as he pursued this quest. It's as if the author intentionally omitted some facts (that the Jefferys was a Harrison commission), and pumped up others (of a rival/foil on the board trying to impede Harrison and the compensation issue; implying that Harrison was jipped) just to make the story more compelling. John Harrison's story, however, is extremely compelling as it is and didn't need this extra spice served up by the author.Do read this (very short) book on how this Mr. Harrison solved the problem of knowing where one is when at sea; and if you're in London, visit the Old Royal Observatory and the Clockmakers museum (in the Guildhall) where you can see Harrison's wonderful creations in person. Enjoy!

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Summary: take it with you around the world
Review: A wonderful short account of how a great obstacle was overcome. Before Global Positioning System satellites, the only way to know where you were on a parallel of latitude (the equator, say, or the Tropic of Capricorn) was to "shoot the sun" at noon and compare the reading with that at a fixed point (Greenwich, say). Ah, but there's the rub! The comparison is useless unless you know what time it is. So navigation depended on creating a timepiece that for all practical purposes would keep accurate time for the months and even years of a sailing voyage. How that timepiece was developed is the story in this book. If you plan to sail around the world, you should own a copy and keep it right beside your GPS receiver!

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Summary: Popular science as it should be written
Review: Longitude is the perfect solution for people who need to kill a few hours. If you are searching for a book or two to take to the beach or on a plane and do not like genre fiction, then Longitude would be a book that I would heartily recommend.

Sobel succinctly recounts the history of John Harrison, a rogue clockmaker who came up with an unconventional approach to the problem of determining longitudinal position at sea. The navigational challenge is an interesting one and Harrison is an attractively unlikely hero.

The writing is crisp, clean and smooth. Note that this is a popular treatment, not a scholarly one. Readers should look elsewhere for extensive notes and bibliography. The book does not require any scientific knowledge to appreciate it and is suitable for virtually every audience.

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Summary: Longitude
Review: I found this book to be a great read and quite informative. The topic is not something that I usually concern myself with, but when I came across the book awhile back, I figured that someday I should read it; that day came, and I'm quite glad I did. It's made me aware of a man I was heretofore not familiar with--John Harrison--and the significance of his inventions. What he accomplished was truly revolutionary, and his story deserves to be known; this highly readable account apptly serves that purpose.

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Summary: A little Gem!
Review: Beutiful writing, surprising history all done with brevity and accuracy. How sailors were able to find their way at sea, and what would happen when they didn't. How ego blocked recognition of the genius who did it. Here is a wonderful little book for your next 3-4 hour airplane travel. We can anticipate more fine writing by Dava Sobel.

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Summary: What a Wonderful Little Read!
Review: We may not designate people "living national treasures" here in the States as they do in Japan, but if we did, Dava Sobel would get my vote in a heartbeat. She has taken on a subject that would be as dry as dust in the hands of almost any other writer and breathed such life into it that you'll have a hard time not reading it in a single sitting.

The problem of determining a ship's longitude at sea may seem now seem obscure at first thought, but it was in fact the premier technological challenge of the age and its resolution helped lay the foundation of the British Empire and thus the modern world.

John Harrison was exactly the kind of common-born, inventive, hard-headed, stubborn, practical, independent-minded Englishman who created the Industrial Revolution, and his lonesome struggle to build an accurate marine chronometer reminds the reader of how great achievement always comes at great cost and as a measure of one's character. His final triumph may look like just a big pocketwatch to us now, but was the first of its kind and did not come easily.

But most of all, "Longitude" is simply a tremendously enjoyable little read, as compact and precisely crafted as the device whose creation it depicts.

Simply a classic.

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Summary: Slightly contradictory, but engaging and worthwhile
Review: Longitude bills itself as "the true story of a lone genius who solved the greatest scientific problem of his time," and in this sense the book delivers. Dava Sobel provides a fascinating account of the state of maritime transport back in the days when no one really knew where he was once he hit the open seas. Sure, anyone could figure out the ship's latitude by looking at the sky, but determining how far east or west one had sailed was another story entirely, and one that included many lethal shipwrecks.

Two 18th century camps emerged to solve the puzzle that offered a 20,000-pound prize. One, supporters of the so-called lunar distance technique, looked to the stars. The other, which included the book's hero, looked to building better clocks. Guess which camp won?

Therein lies one of the books contradictions. Sobel gives due credit to John Harrison for being the first to solve the puzzle by building the world's first seaworthy precision timepiece. Harrison had a gift for seeing what others could not and for turning his vision into durable, seaworthy non-pendulum clocks. (Just try using a pendulum clock at sea and see how long it keeps time.) Learning Harrison's history and his contributions is fascinating reading. But if Harrison solved the longitude problem in the mid to late 18th century and became so widely recognized, why then does Sobel say that the lunar distance proponents produced an almanac and tables from 1766 all the way though to 1907 that "everyone agreed...provided the surest way for mariners to fix their positions at sea"?

Sobel's style is very accessible to the novice. The book is a quick read and packs a lot of interesting information into its 175 pages, although I wish I would have leaned more about Harrison's breakthrough clock called the H-3. I recommend Longitude to all audiences and will turn to another Sobel work, Galileo's Daughter, with anticipation.

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Summary: It All Hangs on a Minute
Review: What is time? Is it anything more than an agreed arbitrary splitting up of a ?day? into shorter intervals? May be not, but the ability to measure those intervals with repeatable accuracy is nowadays taken to be a given fact. For the most part, my ability to tell the time accurately is not a matter of life and death. But for sailors, it once was so.

This thin volume explains the problems of longitude in beautiful clarity. It is not just about the striving for perfection of John ?Longitude? Harrison, but also of two competing solutions to the same problem; that of being able to determine the accurate position of ?here?, in terms of both latitude (which is easy) AND longitude. Harrison was way ahead of his time (pun intended) as he sought to bring order from chaos. Time does not matter if you always have the sun and stars to anchor you to the universal time of your (fixed) location. However, if you move, then there can be significant problems. How do you know how far you are from ?home?? This is especially important to sailors, and the floundering of 4 vessels on the rocky Scilly Isles in 1707 with the loss of more than 2,000 lives was the impetus for creation of the Longitude Board, with its prize of ?20,000.

Harrison chose keeping the time of some fixed place (possibly the port of departure) as a mechanism to determine longitude; every hour difference between actual time and the fixed time means a difference of 15? of longitude. The key to navigation at sea is an accurate record of the fixed time, as a point of reference. There were many innovations and modifications introduced by John Harrison to reduce the number of moving parts, reduce or eliminate the need for lubricants, or compensate for fluctuations in conditions. The restorer of 4 of the timepieces of Harrison was constantly astonished at the innovations that were employed; this restoration work was carried out in the 1920?s and 1930?s, almost 200 years after the first item (?H1?) was completed. That Harrison continued to be his own severest critic spurred him on to improvements that would make his timepieces of an accuracy that many would crave, even into the last quarter of the 20th century.

The author herself readily admits that this is a popular telling of a serious story, yet there is much scope for further serious research if a reader is so inclined. However, the book succeeds in asking important questions of the reader, and invites such to consider the marvels of the universe, almost as an aside. The telling of the tale with simple clarity leads the reader onwards through the self-taught clock engineer?s path as he struggled with the complex difficulties of computing time in a way that compensated for changes in temperature and pressure. This was not the least of his struggles; having built a small version of a timepiece (known as ?H4?) that lost just 5 seconds during 81 days at sea (and hence well within the Board of Longitude?s criteria of tolerance), John Harrison and his son William were made to repeatedly jump through artificial hoops to gain official acceptance. It is significant that the person to meet William on the quayside at the end of a second journey to the West Indies with H4 was Rev Nevil Maskelyne, later to become Astronomer Royal, and someone who had a vested interest in finding fault with the use of timepieces in calculating longitude. There was a determination from some of the early Astronomers Royal to persevere with the lunar method of determining longitude. The prize of the Board of Longitude was never awarded in full, although Harrison was rewarded. However he never jumped through enough hoops to receive the full ?20,000.

The legacy of Harrison is all around us. It is so commonplace that we do not realise that it is there. In some ways the location of the Greenwich Meridian as a fixed point is his legacy. It is therefore fitting that his clocks are on display there. Read this book, and then go and see his clocks on display there. Both are a fitting tribute to someone who was ill-treated and misunderstood at the time.