Longitude is the story of a self-educated carpenter’s improbable invention of the marine chronometer, a saga colored by poisonously envious sabotage, heroic feats of astronomy and a lot of really bad shipwrecks. Dava Sobel has turned a dense thicket of scientific inquiry and discovery into a readable, revelatory tale of adventure that traces the interconnections of Captain Cook, Charles Darwin and Sir Isaac Newton and a number of key characters you likely never heard of. Money is a big motivator – no surprise – merchant trade and royal coffers were both impoverished by the uncertainties of the sea. Solving the navigation problem was critical enough to merit a prize worth the equivalent of millions.
John Harrison was a skilled carpenter who taught himself clockmaking and then set out to create a device that would keep such perfect time at sea that it could determine longitude. Latitude was easy enough. Star siting, sun angles, day length — even an unskilled sailor can find the distance from the fixed equator using those. But the long lines that curve from pole-to-pole were harder to pin down and a tiny mistake, an off-guess, could send you and your ship hundreds of miles off-course, onto perilous rocks in the dark or straight to the bottom of the sea.
The search for longitude inspired great observatories, led to advances in astronomy, engaged such luminaries as Galileo Galilei, Edmond Halley and Isaac Newton and produced the British Longitude Act of 1714 with its enticing cash prize. Harrison set himself to win the prize and created four separate “clocks” that were marvels of technology for his time and that still work perfectly today. He succeeded in developing a workable and elegant chronometer, the first, but not in avoiding the backstabbing and manipulation that nearly cost him the prize.
The story tacks back and forth from Harrison and his endless tinkering to astronomers charting the path of the moon and the positions of the stars. Ships are lost, treasure galleons are pirated, men die of scurvy or go blind squinting at the sun to calculate position. It seems so long ago, in this day of GPS talking cars and satellite positions, that setting out from port meant you were as likely to get lost as you were to get lucky. But one determined, unlettered visionary changed all that and Dava Sobel’s Longitude sheds light on an obscure passage in history that produced important nautical instruments we still use today.
Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time Dava Sobel | Walker Publishing Company 1995