Map, Compass & GPS

Map, Compass & GPS
Wild flowers along Fall Creek on the way to the Green Lakes - Oregon

Sunday, July 1, 2012

Book Review - Longitude

Commonly book reviews focus on the most current publications available on the commercial market.

Still, there aren’t a lot new books for the navigator.
This review is about a book first published in 1995.  The book is Longitude, The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time.  (This is probably the most accurate title of any saga that I have ever read.) Longitude was written by Dava Sobel.  It is available at  either in paperback or as a Kindle edition.

The book is set in England in the 1700’s.  The cast of characters range from Sir Issac Newton to Captain Cook yet focuses on a relatively unknown craftsman, John Harrison.
The measurement of longitude is a critical component of celestial navigation.  It’s grid partner is Latitude.  Prior to the late 1700’s the measurement of latitude had been accomplished for hundreds of years but that was only 50% of the puzzle.   With measurement of latitude, navigators we able to determine an east/west line (like the equator) but nothing to cross that line with a meridian moving north south.  Without that north south component, a ship’s position could not be accurately determined.  For many years Astronomers looked to the movement of celestial bodies to determine the elusive measurement of longitude.  The measurement of longitude through the use of an accurate time piece was discounted. 

Harrison's chronometer
Longitude is the intriguing story John Harrison’s life to design and build an accurate chronometer that could be used by mariners at sea.  The biography is about Harrison progression that began in carpentry and graduated to clock maker and eventually chronometer builder.
Initially, Harrison built case clocks (similar to a grandfather clock.)  In the 1700’s clock mechanisms were built primarily of wood.  Harrison’s talent was to use a variety of woods for gearing and structures with limited use of metals.  He refined his work such that his clocks required no lubrication.  One of his greatest achievements was a large case clock that he built in 1725 that erred by one second in a month.  Prior to this clock, quality clocks were off by one minute each day.  Consider that his work was done by hand without the aid of modern finishing equipment, this was quite remarkable.
Sobel’s book concisely outlines the development of the first four Harrison chronometers and the trials of bureaucracy and envy that Harrison endures for over 50 years.

It wasn’t until trials at sea in the late 1700s that the merit of Harrison’s chronometers became valued.  The naval explorer Captain Cook was an ardent supporter of Harrisons work and achievement. 
This book is a wonderful account of a dedicated craftsman who had a major impact on celestial navigation. 

Update:  In 2000 a film version of Longitude was produced.  It stars Michael Gambon (who played the fatherly wizard Dumbledore in the “Harry Potter” series) and Jeremy Irons.  It’s available on Netflix.

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