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| I ran into this fascinating little book while
wandering through a Barnes & Nobel in Santa Anna, CA
with Jim VanDuzer, looking for a book to read on the
flight back to Cedar Rapids. An easy read in 4-5 hours of
flying and sitting in airports, Longitude tells
the story of one man's efforts to solve the problem of
calculating longitude at sea. Any point on the surface of the earth can be described by two numbers, its latitude and its longitude. Latitude is essentially the north/south distance from the equator; longitude is east/west distance from an arbitrary point. Latitude is relatively easy to calculate. If you know the day of the year, you need only observe the elevation of the sun above the horizon at noon and correct for the tilt of the earth. Longitude, however, is a different story. There's no obvious way to tell how far east or west of a point you are. This became an all-consuming quest in the 18th century. Without the ability to calculate longitude, ships were easily lost looking for small islands or run aground at night when they weren't expecting to be near to land. The search for a solution to the longitude problem was deemed so important that in 1714 the British Parliament passed a law which offered £20,000 (approximately $12 million in today's currency) to the first person who invented a practical method of measuring longitude. This goal launched the life-long journey of John Harrison to create a time piece that could maintain accuracy in the changing climate and gyrations of life at sea. If a ship set a clock to local time at its origin, it could compare the difference between noon at sea and noon on the clock to determine how far east or west of home it was (since the earth takes 24 hours to rotate once about its axis, a four-minute difference in time is equivalent to one degree of longitude from home). The chief rival to this system was computing longitude by reference to the moon's position with respect to the sun and key reference stars and comparing these positions to predicted positions at home. This book is the story of Harrison's quest for the prize and for more and more accurate measurement of time. The intrigue and politics are compelling; Harrison's strongest competitor at one point becomes chairman of the board which is seated to judge the competition for the prize money. The search for longitude becomes intertwined with recognizable events in history. HMS Bounty carried a longitude prize candidate clock, which was commandeered by the mutineers and taken to Pitcarin Island. Capt. Fitzroy of HMS Beagle carried a descendant of the Harrison clocks on the journey which brought one Charles Darwin to the Galopagos Islands. Capt. Cook carried longitude clocks on his travels, including the one which ended in his death on Hawaii. You've got to be a real history and science nut to get a kick out of this, I suppose. I thought it was pretty good reading. |
Longitude:
The True Story of a Lone Genius Who Solved the Greatest
Scientific Problem of His Time