Rating: 
Summary: Good for a Curious Mind
Review: I read this book after someone recommended it to me. It is a book about how the problem of accurately gauging longitude was solved by a clockmaker. It is an interesting peek into England during this time. More than anything though, it is the story of a brilliant, persevering engineer: John Harrison. I would recommend this book to anyone who has a curious, technical mind.Also check out the episode of Nova on PBS entitled 'Lost at Sea: The Search for Longitude'. It is a companion to this book.
Rating: 
Summary: Lightweight
Review: I sought this book out after really enjoying "Galileo's Daughter" by the same author. This book reads like a very early sketch of what could have been an equally substantial and enjoyable book. However it's disappointingly hollow and sparse. A very lightweight read.
Rating:
Summary: An almost waste of time
Review: The book deals with a fascinating subject in a most unfascinating way. In the section devoted to "sources" the author states that "For a few months at the outset, I maintained the insane idea that I could write this book without traveling to England and seeing the timekeepers firsthand." Somehow, although she made the journey, she forgot the point when writing the book. Almost everything of importance is left to the reader's imagination. The book probably does a credible job in dealing with the principle characters and the politics surrounding the challenge. But it is devoid of any depth in dealing with the science and engineering feats that went into the development of the chronometer (which is really the book's major focus) or the alternate methods that were explored to determine longitude. There are no diagrams or meaningful pictures and the treatment of the principles involved are few and very cursory . It is clear that technology is an area with which the author is not comfortable. Then why write a book on a subject where science and technology is the main focus? The lack of pictures, diagrams and meaningful explanations is even more frustrating given the high price of this small paperback. There are much better ways to spend one's time and money.
Rating:
Summary: Interesting topic, sketchily told
Review: The author found a forgotten story to tell which promised to be very engrossing. Unfortunatley, the amount of material unearthed was more conducive to a long magazine article than a book. Considering the amount of publicity this book received I was stunned at how meagre a read it actually was. I found the book very disappointing.
Rating: 
Summary: A Brilliant Tale, Simply Told
Review: Longitude is not nearly as good as it should be. From the rave reviews on this site to the many weeks the book spent on bestseller lists, one would expect it to be an incredibly fascinating, tightly written tale. That it is not. The story itself is interesting...it's amazing to see to what lengths people went to 'discover' longitude and to comprehend just what an enormous problem it was. For teaching us a little bit about the problems of our ancestors, Soebel's paperback is worth the read, just don't expect too much. It is factually rich and does a good job of explaining the intricacies of nautical science to us laymen. In the end, it is the reverse of what the back cover proudly claims: a brilliant tale, simply told.
Rating:
Summary: Well-written story
Review: This is a great book to read, especially because it does a superb job of describing how difficult it was to navigate before Harrison's clocks. I imagine many people are not aware of just how hard it is to get across a giant ocean and not get lost while trying.
Rating:
Summary: Amazing subject, fascinating story
Review: With "Longitude" Dava Sobel has written a very interesting book about the greatest scientific problem of the 18th century. As a result of the 1707-shipwreck story (with a loss of 4 out of the 5 ships), the English Parliament offered in 1714 a 20.000 pounds reward to the person that could provide a practicable and useful way of determining longitude. (If you have forgot, longitude is the "lines" that runs from pole to pole). Not being able to determining longitude was a great problem. Ships spent excessive time trying to find its way back to port, or worse men, ship and cargo were lost at sea. John Harrison (1693-1776) spent his lifetime trying to solve the longitude mystery. Harrison was a son of a countryman, with minimal schooling, and was self-educated in watch making. He made several timepieces, which all qualified for the reward, but the reward was delayed several times by the Longitude committee whom believed that other ways of measuring longitude were the preferred ones. Ultimately after a lot of harassment and trouble, Harrison was given the reward money. Dava Sobel has done a wonderful job in this book, capturing Harrison's fascinating character, his brilliance, preserving and hard working nature. The author has also managed to strike a perfect balance between technical jargon and personal anecdotes, and she does it in such a way permitting the lay readers of the book to admire the elegance of Harrison's discoveries. I believe it is a sign of excellent quality when an author makes learning so interesting. I was hooked from the first page of this book and I read it in 50-page gulps at a time. Highly recommended!
Rating:
Summary: A Good Beach or Airplane Book
Review: This is a highly readable little book, and I recommend it, with a few caveats. Sobel presents her material logically and lucidly. She is a good prose stylist and is obviously an accomplished reporter. This book, however, feels like what it is: a series of articles stretched out a little to accomodate a best-seller format. The story is an intriguing one. An 18th century inventor rises from obscurity and against great odds and bias, produces an instrument that will prove of enormous benefit to his country and to humankind. Just don't go into the reading of this book expecting great historical writing. Sobel acknowledges in a postscript that she doesn't include footnotes "because this book is intended as a popular account, not a scholarly study...". She has culled her research, for the most part, from interviewing historians, attending a seminar, and visiting various sites in England. At least she is forthright about her methodology, so she won't have to face the gauntlet that Kearns-Goodwin and Ambrose have recently had to run (mixed metaphor?). Another minor irritation arises from the fact that one of the prominent blurbs one finds when opening the book comes from Diane Ackerman, whom Sobel later indentifies in her list of acknowledgments as her "dear friend." Again, at least she's being transparent about it, but it still strikes me as a bit disingenuous. To her credit, Sobel does include a rather comprehensive bibliography, so those who want to further investigate Harrison's achievement are well guided. Longitude is a good, quick summer read. For those who want some pith with their punch, however, I would recommend the A&E Sturridge video or CD adapted from this work.
Rating: 
Summary: Harrison was a genius of his time
Review: 222 Years before Dava Sobel's critically acclaimed book was published... Letter dated 20 June, in the Year of Our Lord 1773, in The Thirteenth Year of His Majesty, King George The Third I have prepared this document to press the awarding of the Longitude Prize to Mr. John Harrison, inventor of the five maritime watches over the course of twenty-seven years. Although Mr. John Harrison has received stipends averaging 1,000 pounds throughout the rigorous course of inventing the said watches, I find it more fitting that the sum of 20,000 pounds be bestowed upon him by Board of Longitude. I've had time to get the pertinent facts of the problem from Mr. Harrison, and the crux of the matter lies thence. Lines of latitude run west/east, whereas longitude are the lines running north/south. The difference are that lines of latitude are not consistent re their distance around the Earth, the longest of them being the Equator, designated as 0°. Lines of longitude are equilinear in relation to one another. There have been two studies of thought, that of the use of a maritime clock, and the lunar distance method, endorsed by astronomers such as Sir Edmund Halley and the current Astronomer Royal, the Reverend Nevil Maskelyne. First, the method championed by Mr. Harrison. There are two timepieces used by the captain--the ship's clock, set to home port time and the other a pocket watch which must "not be allowed to run down during the voyage," and is set to local noon by observing the noonday sun. Comparing the two times thus enables the captain to determine his geographic position at sea. The lunar distance method, discovered by our John Hadley, involves calculating in distance between the moon and the stars in the evening sky. The position of the moon within the stars is compared with a table, which contains the time such a position was observed at home port, and the time difference calculated. The flaw with that approach is due to the effect overcast nights have on lunar and stellar observation. My hat is off to Mr. Harrison himself, horologist extraordinaire, and the meticulous genius and the spirit of perfection that has gone into his quintet of timepieces. Five years for H-1, four years for H-2, twenty for H-3, and a year or two apiece for H-4 and H-5: if that does not embody scientific aptitude at its zenith, then may Sir Isaac roll in his grave for eternity! His watches has no pendulums, nor the necessity of lubricating the parts with oil. Pendulums functionally ideally in stationary environments, not aboard the constant pitching and moving of a ship at sea, where the clock's speed would slow, speed up, or stop altogether. Harrison has used metals that are not only rust-proof, but by having metals that counterract any contraction or expansion, thereby maintaining a balance. We have evidence that works in our favour, in particular, the performance of his fourth watch, H-4, as tested aboard the H.M.S. Deptford on November 1761. After eighty-one days at sea, from London to Port Royal, Jamaica, results showed that the watch had lost only five seconds! There was a violent storm on the return trip back to England, during which time the watch lost just under two minutes. A recent test of his latest watch, named the H-5, was performed for the benefit of His Majesty, George the Third, who was suitably impressed with the results. If His Majesty was impressed, so should the members of the Longitude Board. In conclusion, John Harrison, with his efficient, durable, and portable timepiece, has given our kingdom mastery of the seas over other Europeans and the Barbary pirates. We can now set an infinite variation of courses to avoid detection from our enemies. Harrison is entitled to stand alongside the many who have made England great. Yours etcetera the Right Honorable D.J.H.
Rating:
Summary: Entertaining story, missed diagrams and maps
Review: I picked this up as part of my "naval history and nautical fiction" kick. The book is small, and can be easily read. The language is simple enough so that someone who has nearly forgotten her geography and physics (like me)can follow the basic problem. The story is not so much that of John Harrison, the man who solved the longitude problem, but of the whole issue. The issue was simple and yet difficult - sailors were travelling out further and further in the search for spices, gold, other precious commodities and of course, slaves. [Not to mention, land and religious converts]. As trade expanded from the Mediterranean and via the Middle East to the Orient (for reasons not explained in this book and somewhat missed), sailors found themselves either hugging the African coast and then the Arabian and Persian coastline to India (and beyond), or travelling other routes to the fabled riches of the Orient, the Americas, and so forth. The first option had some problems, notably pirates not to mention intense competition. The second route - across the Atlantic and Pacific oceans - meant traversing the oceans without sight of land. In an era, where the only method of reckoning your location was latitude (through the position of the sun) and a compass, disasters resulted frequently. Sometimes, navigators discovered new continents (such as the Americas) in an effort to find a new route to India; more often, they were shipwrecked. Vessels that managed to find any landing point often lost precious time, which meant lack of fresh water and also the disease of scurvy which took as many or more lives. Dava Sobel illustrates the problem of shipwreck with the story of Cloudesley Shovell who wrecked four out of five ships just off the British coast in 1707, and the subsequent near-disaster of Anson's around-the-world voyage where most of his ships were lost. However, the problem of finding a ship's location through longitude had been an issue even earlier, as rewards offered by the Spanish Crown, the French, and other governments attested. What is interesting about this book is not that Dava Sobel shows us how a self-educated watchmaker solved the problem of longitude decisively, despite opposition from those preferring to rely on astronomy, but that the whole problem is placed in the context of scientific discoveries and the growth of European trade with the rest of the world. Many of the achievements of Galileo were driven by his efforts to solve the longitude problem, and to claim the prize offered by Philip II's Spain. Similarly, the work of other astronomers was driven as much by desire to solve this intractable problem (and claim the rich rewards) as to make further astronomical discoveries. As for the commercial aspects, the plight of ships driven off course, or relying on a few known routes (and thus at the mercy of pirates and privateers) was well-known, enough to seriously upset merchants. They demanded that the British Parliament offer a reward to solve the problem, and this coupled with the 1707 disaster off the Scilly Isles, was what prompted the famous reward offered for discovering the secret of longitude.
How could navigators with no land in sight determine where they were? Latitude was easy enough, but longitude (the lines that run from pole to pole) could not be determined with exactitude. Even a small error could be costly, leading to missed landfall and subsequent shipwreck or almost as costly errors in navigation. [Anson's plight, sailing back and forth and missing his landfall by just a few miles, illustrates this well]. Many captains used a method called dead reckoning, but this was not accurate. One solution was obviously to have two watches, one with the local time and the other with the time in London - but timepieces were notoriously unreliable at sea.
Dava Sobel spends the major part of the book explaining not only how John Harrison, from Yorkshire, built a series of brilliant timepieces, some of them friction-free, that solved this problem once and for all. While his timepieces were too expensive for ordinary naval officers to buy, subsequent watchmakers built cheaper versions that were eventually available on the market. Captain Cook made his famous voyage using a timepiece based on Harrison's near-final version. If that were all, the book would be interesting enough, but Sobel goes further to show how Harrison's reward was delayed by the machinations of those who believed that astronomy offered a superior answer, not to mention Harrison's own perfectionism. [If he had offered his first version to the Board and not criticized it, he would have obtained the reward faster - a lesson perhaps to would-be inventors in subsequent decades]. While this was a fascinating read, I really missed maps and diagrams. While the version I read was a paperback, I felt that a few sketches and illustrations would not have hurt. I am told that the illustrated version of this book makes for a better read. I should also add that this book is not a biography of Harrison and his son, but a look at the whole issue of longitude in the context of scientific discovery and the growth of trade and exploration.
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