Inventor and horologist, born in Foulby, West Yorkshire, N England, UK. By 1726 he had constructed a clock with compensating apparatus for correcting errors due to variations of climate. In 1713 the British government had offered three prizes for the discovery of a method to determine longitude accurately (only possible with very accurate timepieces). After long perseverance he developed a marine chronometer which, in a voyage to Jamaica (17612) determined the longitude within two geographical miles. After further trials, he was awarded the first prize (176573).
John Harrison (March 24, 1693–March 24, 1776) was an English clockmaker, who designed and built the world's first successful chronometer (maritime clock), one whose accuracy was great enough to allow the determination of longitude over long distances.
Overview of the problem
A place's longitude is how far around the Earth it is from a reference point, say London — usually measured in degrees (360 degrees is a complete circuit of the world). Many solutions were proposed for how to determine longitude at the end of a sea voyage, and therefore the longitude of the place you have just discovered (in case, for instance, you want to go back one day, or simply put it on a map).
Harrison instead set out to solve the problem in probably the most direct way: by producing a reliable clock. Frisius had realised that to determine longitude a clock would have to be “of great exactness”. Huygens had trialled both pendulum and a spiral balance spring clocks as methods of determining longitude. But when longitude at sea is lost, it cannot be found again by any watch.” However, if such a clock were built and set at noon in London at the start of a voyage, it would subsequently always tell you how far from noon it was in London at that second, regardless of where you had traveled.
Harrison in Lincolnshire
Harrison was born at Foulby, near Wakefield, in Yorkshire. First following his father's trade as a carpenter, Harrison built and repaired clocks in his spare time. As clocks and watches of all kinds were rare and expensive at the time, and Harrison came from a family of only modest means, it is likely the legend is false or the timepiece was broken enough to be worth little.
He built his first longcase clock in 1713, at the age of 20. Three of Harrison's early wooden clocks have survived;
He was a man of many skills and used these to systematically improve the performance of pendulum clocks.
The first three marine timekeepers
In 1730 Harrison made a description and drawings for a proposed marine clock to compete for the Longitude Prize and headed for London seeking financial assistance. He must have been impressed by Harrison, for Graham personally loaned him money and told him to build a model of his marine clock.
It took Harrison seven years to build Harrison Number One or H1. He showed it to members of the Royal Society who spoke on his behalf to the Board of Longitude. Harrison sailed to Lisbon and back aboard two naval vessels, and on their return both the Captain and the Master (navigator) praised the design. The Master noted that his own calculations had placed the ship sixty miles east of its true landfall which had been correctly predicted by Harrison using H1.
This was not the transatlantic voyage demanded by the Board of Longitude, but the Board was impressed enough to grant Harrison 500 pounds for continued work. Harrison moved on to develop a more compact and rugged version, H2. H3 had proved a very valuable experiment, teaching Harrison a huge amount about the design and making of balance springs and it left the world two enduring legacies — the bimetallic strip thermometer and the caged roller bearing.
The longitude watches
Based on a watch made to his designs by John Jefferys, he proposed to build two new timekeepers, a larger and a smaller watch.
H4 took six years to construct, and Harrison, by then 68 years old, sent it on its transatlantic trial in the care of his son, William, in 1761. When the ship returned Harrison waited for the £20,000 prize, but the Board refused to believe the accuracy was not just luck, and demanded another trial. The Harrisons were outraged and demanded their prize, a matter that eventually worked its way to Parliament, which offered £5,000 for the design. The Harrisons refused but were eventually obliged to make another trip, to the Caribbean city of Bridgetown, on the island of Barbados to settle the matter.
At the time of the trial, another method for measuring longitude was being developed to the point where it was ready for testing, the Method of Lunar Distances.
On Harrison's second H4 trial, the Reverend Nevil Maskelyne was asked to accompany the ship and test the Lunar Distances system.
Unfortunately, Nevil Maskelyne had been appointed Astronomer Royal on his return from Barbados, and was therefore also placed on the Board of Longitude. He returned a report of the H4 that was negative, claiming that the "drift rate" of the clock, the amount of time it gained or lost per day, was actually an inaccuracy, and refused to allow it to be factored out when measuring longitude.
Harrison started work on his H5 while the testing was continuing, with H4 being effectively held hostage by the Board. Harrison felt "extremely ill used by the gentlemen who I might have expected better treatment from" and decided to enlist the aid of King George III. King George tested H5 himself at the palace and when it had lost only four and a half seconds in ten days he was outraged and is said to have stormed "By God Harrison, I'll see you righted!", and told Harrison to petition Parliament for the full prize after threatening to appear in person to dress them down. So in 1773, Harrison finally received his reward.
James Cook used K1, a copy of H4, made by Larcum Kendall who had been apprenticed to John Jefferys on his voyages. The cost of these clocks was so high (a significant fraction of the cost of the ship) that the Lunar Distances method would complement and rival the marine chronometer for the next hundred years.
Memorials
Harrison died on his eighty-third birthday and is buried in the graveyard of St John's Church, Hampstead along with his second wife, Elizabeth and their son William. His tomb was comprehensively rebuilt in 1879 by the Worshipful Company of Clockmakers even though Harrison had never been a member of the Company.
Harrison's last home was in Red Lion Square in London, now a short walk from the Holborn Underground station. There is a plaque to Harrison on the wall of Summit House in the south side of the square. A memorial tablet to Harrison was unveiled in Westminster Abbey on the 24th of March 2006 finally recognising him as a worthy companion to his friend George Graham and Thomas Tompion,"The Father of English Watchmaking" who are both buried in the Abbey. The memorial shows a meridian line (line of constant longitude) in two metals to highlight Harrison's most widespread invention, the bimetallic strip thermometer.
Subsequent history
After World War I, Harrison's timepieces were found in a highly decrepit state in storage at the Royal Greenwich Observatory, by a retired naval officer, Rupert Gould, who spent many years documenting, repairing and restoring them. It was Gould, not Harrison, who gave them the designations H1 through H5. It includes a very detailed description of the work of Harrison, as well as discussion of the subsequent evolution of the chronometer.
Today the restored H1, H2, H3 and H4 can be seen on display in the National Maritime Museum at the Royal Observatory, Greenwich.
In the final years of his life, John Harrison wrote about his research into musical tuning and manufacturing methods for bells. In 2002, Harrison's last manuscript, "A true and (short, but) (*crossed out) full Account of the Foundation of Musick, or, as principally therein, of the Existense of the Natural Notes of Melody:" was rediscovered in The US Library Of Congress.
Following a major Symposium on the Longitude Problem at Harvard University, Dava Sobel wrote a book in 1995 chronicling the history of John Harrison's invention, titled, "Longitude: The true story of a lone genius who solved the greatest scientific problem of his time." The account was dramatised in the 2000 film Longitude starring Michael Gambon as Harrison and Jeremy Irons as Gould.
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