Showing of next show all A very enjoyable story about a rogue clock-maker who solved the longitude problem and made ocean going ships destination more accurate. I read this over a few months over break at work its a short book. Its well written, with an interesting cast of characters, and has a well described history of longitude.
A stable surface to work from, known coordinates to refer to, a sheltered environment for the unstable chronometers of the day, and the ability to repeat determinations over time made for great accuracy. For calculating longitude at sea however, early ocean navigators had to rely on dead reckoningwhich involves triangulating several bearings of the same land feature from different positions.
Once out of sight of land, longitude became impossible to calculate, which sometimes led to tragedies in stormy or foggy conditions. In order to deal with not being able to calculate longitude, captains would sail to the known latitude of their destination, and follow the line of constant latitude home.
This was known as running down a westing if westbound, or easting if eastbound. Determining latitude was relatively easy in that it could be found from the altitude of the sun at noon with the aid of a table giving the sun's declination for the day. Latitude can also be determined from night sightings of Polaristhe northern pole star.
However, since Polaris is not precisely at the pole, it can only provide accurate information if the precise time is known or many measurements are made over time, which made developing an accurate chronometer for long ocean voyages even more vital.
Navigating purely by latitude was of course vulnerable if the sun was clouded over at noon, and caused problems as it prevented ships from taking the most direct route, a great circleor a route with the most favourable winds and currents, extending voyages by days or even weeks.
This increased the likelihood of short rations,  scurvy or starvation leading to poor health or even death for members of the crew and resultant risk to the ship.
Errors in navigation also resulted in shipwrecks.
Motivated by a number of maritime disasters attributable to serious errors in reckoning position at sea, particularly spectacular disasters such as the Scilly naval disaster of which took Admiral Sir Cloudesley Shovell and four ships of his fleet, the British government established the Board of Longitude in Each prize, in increasing amounts, was for solutions of increasing accuracy.
These prizes, worth millions of dollars in today's currency, motivated many to search for a solution. Britain was not alone in the desire to solve the problem. It was charged with, among a range of scientific activities, the improvement of maps and sailing charts and advancement of the science of navigation.
Holland added to the effort with a prize offered in Due to the international effort in solving the problem and the scale of the enterprise, it represents one of the largest scientific endeavours in history.
Knowing Longitude[ edit ] A blue plaque marks the location at Red Lion Square the original house was demolished where Harrison lived and died. As Dava Sobel explains, "to know one's longitude at sea, one needs to know what time it is aboard ship and also the time at the home port or another place of known longitude-at that very same moment.
The two clock times enable the navigator to convert the hour difference into geographical separation. And so each hour's time difference between the ship and starting point marks a progress of fifteen degrees of longitude to the east or west.
Every day at sea, when the navigator resets his ship's clock to local noon when the sun reaches its highest point in the sky, and then consults the home port clock, every hour's discrepancy between them translates into another fifteen degrees of longitude.
One degree of longitude equals four minutes of time the world over, although in terms of distance, one degree shrinks from Precise knowledge of the hour in two different places at once - a longitude prerequisite so easily accessible today from any pair of cheap wristwatches - was utterly unattainable up to and including the era of pendulum clocks.
On the deck of a rolling ship such clocks would slow down, or speed up, or stop running altogether. Normal changes of temperature encountered en route from a cold country of origin to a tropical trade zone thinned or thickened a clock's lubricating oil and made its metal parts expand or contract with equally disastrous results.
A rise or fall in barometer pressure, or the subtle variations in the Earth's gravity from one latitude to another, could also cause a clock to gain or lose time. A practical solution came from a gifted carpenter, John Harrison, who solved one of the most difficult problems of his time by creating an accurate chronometer.
The best scientists of the time, including Sir Isaac Newtonthought it impossible. Harrison spent four decades perfecting a watch that would earn him compensation from Parliament although not the prize established by the Longitude Act of thanks to the recognition and influence of King George III of England.Reviews 'Longitude' reviewed by Charlotte Mulcare Longitude: The true story of a lone genius who solved the greatest scientific problem of his time by Dava Sobel Longitude was first published in , occupying a substantial portion of many a Waterstones table around Christmas−time.
The book has endorsements from Patrick . Longitude: the true story of a lone genius who solved the greatest scientific problem of his time. [Dava Sobel] -- Lacking the ability to measure their longitude, sailors throughout the great ages of exploration had been literally lost at sea as soon as they lost sight of land.
This item: Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time by Dava Sobel Paperback $ In /5(). The Illustrated Longitude: The True Story of the Lone Genius Who Solved the Greatest Scientific Problem of His Time 1st (first) Thus Edition by Sobel, Dava published by Walker & Company () out of 5 stars 1,/5.
Longitude is the dramatic human story of an epic scientific quest and of Harrison's forty-year obsession with building his perfect timekeeper, known today as the chronometer.
Full of heroism and chicanery, it is also a fascinating brief history of astronomy, navigation, and clockmaking, and opens a new window on our world/5(). Buy a cheap copy of Longitude: The True Story of a Lone book by Dava Sobel. The thorniest scientific problem of the eighteenth century was how to determine longitude.
The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time. ISBN: ISBN Longitude: The True Story of a Lone Genius 5/5(5).