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

Although this book is small, the material still had to be stretched to get as far as it went. For anyone interested in a look at 17th and 18th politics, science and nefarious dealings, however, this book is for you. And it's a one day read. I would recommend this book for a high school or undergraduate level science project; the book does presuppose some knowledge of plane geography. You also get some interesting by-products of the quest for the way to determine longitude on the high seas.

I won't bother telling you what the book was about, as a few hundred people have already explained it in their reviews, so I will simply explain what the book got right and what it was missing.

First, it was an excellent popular-level introduction to John Harrison, the longitude problem, and the invention of the watch sturdy enough and precise enough to measure time with extreme precision aboard a ship to allow for the calculation of longetivity. Sobel presents the information in a very clear way (for the most part), and does not (often) delve into technical discussion which the average reader will not understand. I personally learned quite a bit from this book, as it was my first exposure to the longitude issue and John Harrison. I did not know that either existed before reading this book, and now I think I have an adequate grasp of both, so this book was a success.

However, it could have been better. Much better. As other reviewers have noted, this book REALLY needed some pictures, or diagrams, or something. A description of an incredibly complex clock/watch does NOT really help the average reader know how it worked, or even what it looked like. There were a number of times that Sobel would describe what Harrison did to his invention, and I wouldn't really understand exactly what was happening. I fail to understand why some diagrams or illustrions were not included, as their absence is glaringly obvious and irritating.

Other than that, my only complaint is that it was a little short and could stand to have a bit more detail. I understand that it is a popular book, but it was still a bit on the skimpy side when it came to details. It seemed to spend lots of time giving details about the longitude problem, then the last part of the book just sped through the life and inventions of Harrison without really getting into detail. It had a somewhat rushed feel, and I really think the book would be significantly better if it had about another 25 pages or so added to the Harrison section.

In short, the only things that separate this good book from being a great book are the lack of diagrams/illustrations and the slightly annoying lack of detail toward the end of the book. It's not as good as Galileo's Daughter, but it's a pretty good book I'd recommend reading, especially since it will only take a few hours.

Overall grade: B+

The last years of the seventeenth century and the first years of the eighteenth century saw the rise of significant global commerce. With few land routes and none capable of handling large amounts of cargo, the only option for shipping was via the oceans. As long as the ships stayed within sight of land, they generally knew where they were. However, that had its' dangers as it was always possible that a storm would dash the ship onto the land. Furthermore, many of the new voyages required movement across vast areas of ocean, and to do so safely it is necessary to have an accurate way to determine the location of the ship.
Fixing the latitude was easy, as long as the position of the sun could be determined; it was possible to determine the latitude. Therefore, only the most overcast of days prevented the navigators from computing the latitude. However, fixing the longitude was much more complex and several ways were put forward. All involved some form of timekeeping, if you knew your local time and the time at a fixed point or longitude zero, the difference could be used to fix the longitude. Determining the local time was again easy and also involved determining the current position of the sun. Unfortunately, keeping the time of longitude zero was very difficult.
All of the timepieces of the era were inherently inaccurate and grew even more so when they were jostled about by the rolling of a ship. Since being off by even a few minutes could be critical, it was necessary to have a clock that was sturdy and accurate. The problem was considered so significant that in 1714 the English Parliament offered an enormous reward for a solution.
John Harrison believed that a solution was possible and after years of effort, he developed one. In the process he solved some very complex mechanical problems. Due to the wide range of temperatures that the clock would be exposed to, the expansion and shrinking of metals would cause the clock to vary. His solution was to put two different metals together so that the changes would offset each other. This strategy is the basis of the modern thermostat.
A second problem was one of lubrication. If the moving parts were not lubricated, the friction would cause wear that would lead to imprecision. If a lubricant were used, the changing temperatures would lead to a change in viscosity and also lead to imprecision. His solution was to use a wood that secreted a lubricant and his end result was a clock that was extremely accurate and very sturdy.
This is a fascinating story of mechanical genius that has probably never been equaled. Harrison's clocks kept a time so accurate that it was not superseded for centuries. It is a demonstration that humans are so intelligent and resourceful that when a major problem exists that must be solved, a solution will be found. That is a comforting thought as the human race continues to face increasingly greater and more complex environmental problems.

Prior to 1773 navigation and mapping were hampered by the difficulty of determining longitude on open sea. Determining latitude, the angular distance north or south of the equator, was easy; it only required being able to measure the angle of a star above the horizon. Determining longitude, the angular distance east or west of an arbitrary meridian, required the ability to keep time. Until the advent of an accurate timekeeper the only way a navigator could fix his longitude was to estimate the distance he had covered.

The accuracy of the hypothetical timekeeper was critical. For a ship to arrive within about ten longitudinal miles of its destination on a voyage of three months, sometimes the difference between life and death for the crew, the timekeeper could neither gain nor lose more than one second a day. The problem became a national quest in eighteenth century England where a "board of longitude" offered the modern equivalent of twelve million dollars for a solution.

The problem was finally solved by John Harrison, a Yorkshire native who never saw the inside of a school. His life-long struggle to build a sufficiently accurate clock and to win the monetary award despite seemingly insurmountable political obstacles is one of the most inspiring stories in the history of science.

Dava Sobel is master science writer. Although other writers (Lloyd Brown, for instance) wrote engagingly on this subject, LONGITUDE is the first comprehensive book-length treatment for lay readers. It flows as smoothly as a novel. Don't expect footnotes and diagrams; it's not a scientific monograph. Don't expect instructions on navigation or clockmaking; it's a popular narrative, not a Popular Mechanics article. Expect tight, efficient writing and a window into a fascinating episode from centuries past.

A "simple" invention that literally opened the world and a man who spent his entire life figuring our how to make it happen, made for a fantastic story ... and a rare book that I really couldn't put down.