“Longitude” by Dava Sobel is a wonderful little book.
It tells the story of one of the most vexing mysteries faced by mankind: the Longitude Problem. For thousands of years of human exploration, sailors didn’t where they were once they lost sight of land. Oh they could figure out Latitude (North-South location) easily enough, by measuring the altitude of the sun. However, knowing their Longitude (East-West location) was impossible. Once they lost sight of land, they were literally lost at sea.
The main method of estimating Longitude was “dead reckoning”, which is exactly as it sounds: point the ship in one direction, and try and measure how far it travels every day to estimate its Longitude.
The search for a better method had baffled scientist for so long that in 1714 England’s Parliament passed the Longitude Act, which created the Board of Longitude and offered a King’s Ransom of 20,000 British Pounds (approx. $15,000,000 in today’s U.S. Dollars) to whoever could come up with a solution to the Longitude Problem.
The greatest European scientific minds of the time were involved in the attempts to find solutions to the Longitude Problem and claim the prize. Among these were Galileo, Sir Isaac Newton, Leonhard Euler, Domenico Cassini, the British Royal Observatory, the Paris Observatory, and Edmond Halley.
The search for a solution led to a mapping of the celestial heavens, of the discovery of the speed of light, but ultimately to the invention that would change the world: portable time, in the form of the chronometer.
While astronomers spent their entire lives attempting to map the visible heavenly objects as a solution to the problem, a self-taught Watchmaker by the name of John Harrison toiled for over 40 years to perfect a chronometer that would not only allow people to “carry” their home time with them away from the town square, but also allow for ships to carry the most accurate way for them to find their location. Soon the pocket chronometer would be mass-produced to the point where it would facilitate the British Navy’s mastery over the Oceans, and therefore contribute directly to the creation and duration of the British Empire:
When the Board of Longitude disbanded in 1828 at the repeal of the prevailing Longitude Act, its chief duty, ironically enough, had become the supervision of testing and assigning chronometers to ships of the Royal Navy.
It was not uncommon for one ship to rely on two or even three chronometers, so that the several timekeepers could keep tabs on each other. Big surveying ships might carry as many as forty chronometers. Records show that when H.M.S. Beagle set out in 1831, bent on fixing the longitudes of foreign lands, she had twenty-two chronometers along to do the job. Half of these had been supplied by the Admiralty, while six belonged personally to Captain Robert Fitzroy, who had the remaining five on loan. This same long voyage of the Beagle introduced its official naturalist, the young Charles Darwin, to the wildlife of the Galapagos Islands.
In 1860, when the Royal Navy counted fewer than two hundred ships on all seven seas, it owned close to eight hundred chronometers. Clearly, this was an idea whose time had come. The infinite practicality of John Harrison’s approach had been demonstrated so thoroughly that its once formidable competition simply disappeared. Having established itself securely on shipboard, the chronometer was soon taken for granted, like any other essential thing, and the whole question of its contentious history, along with the name of its original inventor, dropped from the consciousness of the seamen who used it ever day.
“Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time” is a fascinating, FASCINATING read, of a period in history which still affects us.
The book is short (175 pages in my paperback edition), and it mostly refrains from direct quotes and dry facts, rather choosing an elegant, narrative form, as if sharing its story with a close friend.
Definitely recommend.
Tags: chronometer, Dava Sobel, John Harrison, Longitude, review
