Wooden Watches (Longitude - Dava Sobel)

Name: MALU

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Product:	Longitude - Dava Sobel
Date:	07/01/07 (345 review reads)
Rating:

Advantages: informative and readable

Disadvantages: none

Do you know where John Harrison is buried? I do, because I’ve been to his grave, twice even, the last two times I was in London with students I booked a tour through Hampstead with London Walks and the guide showed us Harrison’s grave in the churchyard of St John’s Church. I see you frowning and scratching your heads: John Harrison? To be honest, when I saw the name on the tombstone, I didn’t know who that was, either, and when the guide mentioned that that man had solved the longitude problem, I wasn’t much wiser. The guide didn’t dwell on the subject and only after reading the book Longitude by Dana Sobel, I understood that I had paid homage to a genius.

The American Dava Sobel (born in 1947 if I’ve counted correctly, I couldn‘t find precise biographical data) was a science reporter for the New York Times covering scientific research and the history of science and has written and co-written several books on science topics, all highly praised and awarded for their information and readability and translated into many languages.

This first 60 pages (of 175) of the book describe the problem and the various ideas to solve it before Harrison’s time. Already before the birth of Christ learned men had thought of a pattern of lines - latitudes and longitudes - that could help to determine any given spot on the surface of the earth. The equator marked the zero degree parallel of latitude fixed by the laws of nature, but where to put the zero degree of longitude? According to who was working on the problem it shifted from the Canary and Madeira Islands to the Azores and Cape Verde Island, to Rome, Copenhagen, Jerusalem, St. Petersburg, Pisa, Paris and Philadelphia before it finally ‘settled’ in Greenwich.

Any place would have done in fact, the problem proper was to find out how far a ship was away from the zero degree of longitude so that its position could be determined. The captains knew along which latitude they were sailing, they had instruments to help them (the compass was invented in China in the 11th century and reached Europe in the 13th century), but they had no instruments to determine the distance from the zero degree of longitude. Sobel describes some of the methods people used which appear to us fantastical or outrageously silly; the disasters which happened because the captains didn’t know where they were touched me deeply, the successful voyages of the great explorers we know about were more or less due to luck or God’s grace - whatever people chose to believe.

In 1714 the British Parliament passed the Longitude Act offering 20,000 GBP ‘for a method to determine Longitude to an accuracy of half a degree of a great circle’. That was the age of Newton and Halley (of comet fame) and other learned scientists, they all favoured and worked on the so-called lunar distance method, they watched, measured and wrote down the distance of the wandering moon in relation to the stars by night and the sun by day, they wanted to provide the sailors with a map of the sky with which they could determine their position. This method did save many lives, however, the problem remained what to do during spells of inclement weather.

Enter John Harrison, born in Foulby, near Wakefield, in Yorkshire in 1693, son of a carpenter. He worked together with his father as a young man and repaired clocks in his spare time, later he dedicated his life to the invention of marine timekeepers - supported by men who believed in his work - clocks that would travel on the ships across the oceans always showing Greenwich Mean Time uninfluenced by the movements of the ship, by heat or cold or humidity; the captains could then compare noon on the ships with the time on the clock, the difference would tell them how far they were away from Greenwich and with this their exact position.

Reading about Harrison’s indefatigable work, he built three clocks entirely of wood and one watch of metal and precious stones, his successes and failures, the political intrigue and foul play he encountered, what happened to his chronometers after his death I found myself engrossed in a historical period and problems I had known nothing about. I became so interested in the subject that I thought I’d read up on John Harrison on Wikipedia to learn even more which proved to be an insult to Dava Sobel. All the facts are in her book but in a more appealing way, by personalising dry historical facts, by empathising with the characters she describes she makes history come alive. This is not faction, a mixture of facts and fiction, no, she sticks to the facts but breathes life into them.

I must admit I haven’t only seen John Harrison’s grave but I’ve also been to the Observatory in Greenwich several times before reading Sobel‘s book, I must have seen Harrison’s clocks without ’seeing’ them, I could bite my back bottom (as the Germans say), the only way to set my mind at rest is to go there again . . . If a book has such an effect, it deserves five stars, doesn’t it?

Harper Perennial
184 pages (including the index)
Cover price 7.99 GBP

Summary: the story of John Harrison