Wednesday, September 28, 2016

Book Review: Longitude, By Dava Sobel

***From Apprentice Corner: Book Review

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

Longitude, written by Dava Sobel, tells the story of John Harrison, an inventor of the highest magnitude who spent over 40 years feverishly devoted to solving the greatest scientific problem of his time.

The book has been adapted into a TV series, won the British Book of the Year in 1997, as well as many other awards. So much praise has been heaped on this book that I needn’t add to the chorus, but I feel it necessary to give the book a brief introduction for those that might not have heard of it.

In the days long before GPS, sailors used a technique known as ‘dead reckoning’ to figure out their position, wherein sailors would calculate their position at sea using a known previous position and advancing that position based on estimated speed and direction. With wind, tides, imperfect measuring instruments and a whole range of other variables affecting the calculation, what could possibly go wrong?

A lot did, and often. Even after improvements in celestial methods that helped determine longitude, the problem persisted. The most accurate lunar tables still had errors (errors which compounded based on your position on Earth) and they relied on cooperative weather to be of any use at all. One degree of longitude equals approximately 111 kilometres; the slightest error in calculation meant the difference between running aground or perhaps never seeing land again!

The costs to the seafaring nations were enormous. Precious cargo and thousands of lives were lost. The British, French and Spanish governments offered enormous rewards for any one person able to resolve the problem, but most laboured in vain. Many of the greatest clockmakers and scientists ranging from Galileo to Edmond Halley gave it a shot. Isaac Newton implied that the dilemma was unlikely to be resolved by mechanical means. The fact that one man was able to satisfactorily resolve the problem with his incredible marine chronometer is hard to fathom.

The trials and tribulations of John Harrison, the competing designs and the plots of the sailors that so desperately needed a resolution to the problem are beautifully documented in Longitude - Dava Sobel is one of the finest science writers on the planet. I won’t comment too much on her extraordinary science writing ability but suffice to say that you won’t be left perplexed by any concepts at any point and will be enthralled throughout.

Of particular relevance, the Australian National Maritime Museum in Sydney has an exhibition on now titled Ships, Clocks and Stars,featuring many navigational instruments used back in the day, replicas of John Harrison’s early clocks and his original H-4 watch - the very watch that practically solved the problem once and for all. The exhibition finishes on the 30th of October so you’d best get in quick!

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