In our latest article, we delve into the life and work of clock maker John Harrison, who revolutionised sea navigation with his marine chronometer, and we investigate why it took almost 250 years after his death for his work to be vindicated.
Originally a carpenter, John Harrison (1693-1776) was a Yorkshireman. Today, he's celebrated as the inventor of the marine chronometer, a prize-winning watch that enabled the accurate determination of longitude at sea - revolutionising navigation and increasing the safety of sea travel.
The Longitude Act (1714)
During the 17th and 18th centuries, the inability to accurately pinpoint the longitude of a sea vessel had led to many disasters, including the Scilly naval disaster (1707) in which 2,00 sailors perished due to poor navigation. As a result, the British Government passed The Longitude Act (1714) and offered up to £20,000 (£4m today) for anyone who could find a simple and practical method for the precise determination of a ship's longitude.
Having previously designed precision longcase clocks – accurate to one second in a month – Harrison’s goal was to design a portable clock more accurate than any other of the time, to claim the reward.
The H1 – Harrison’s first attempt
Harrison’s first attempt, the H1, essentially a portable version of his precision timepieces, featured a pair of interconnected swinging balances that remained unaffected by a ship’s movement. Live testing at sea was called for and in 1736, the H1 made the round trip to Lisbon. Following the success of this test, the Commissioners of Longitude awarded him £500 (to be paid in two halves) to facilitate the design of an improved piece.
Harrison’s H2 and H3
Harrison’s second attempt, the H2, was completed within two years but never got to the trial stage as Harrison himself identified a flaw.
In 1740, the H3 was started, with work on it continuing for almost two decades until Harrison conceded that this model would not be able to maintain the accuracy required.
The Harrison Sea Clock – H4
By the mid-18th century, Harrison had commissioned John Jefferys to design a watch with an innovative type of balance for his personal use, which he went on to include in his fourth attempt. In 1761, Harrison’s H4 was sent on a round trip to Jamaica as a live trial. It received mixed reactions with the ship’s captain wanting to purchase Harrison’s next model, but the Commissioners deciding the test to Jamaica was just not enough.
A second trial – this time to Barbados – was arranged to be carried out alongside a trial using astronomical methods, to be conducted by Nevil Maskelyne. The Board confirmed that Harrison’s H4 had kept to the stringent time limits but insisted it be re-tested to ensure it could be produced by others. This retesting was carried out at the Royal Observatory by Maskelyne and, after 10 months, Maskelyne deemed that the H4 had underperformed.
The Harrison Sea Watch – H5
The resistance from Maskelyne may well have originated from his role as Astronomer Royal but his obstruction took its toll on Harrison who began work on another iteration, the H5. He took this to an audience with King George III who tested it himself, over ten weeks and found it to be accurate to within one third of one second per day.
At the age of 80, John Harrison received a parliamentary financial award, although he never received the official award.
The Harrison Lesser Watch
While it was Harrison’s H4 marine chronometer that was the breakthrough in determining longitude accurately, his conceptual ‘lesser watch’ or H6 was a pocket watch design that he had floated to the Board of Longitude. Believed never to have been built and existing only in design form on paper, it was this timepiece that was immortalised in Only Fools and Horses, finally making Del Boy and Rodney millionaires in the classic sitcom.
How John Harrison had the last laugh
Fast forward over 240 years and we see how John Harrison was finally vindicated of all the ‘absurd’ claims he was accused of making.
Following his successful H4, Harrison attracted much ridicule and criticism when he vowed to create a pendulum clock that would be accurate to within a second across a period of 100 days. His contemporaries simply scoffed, saying it was impossible.
He wrote a book outlining the design for this timepiece which detailed a large pendulum arc, a light bob, and a recoil grasshopper escapement. Savaged by critics, Harrison’s ideas were largely forgotten until the 1970s when Martin Burgess deciphered Harrison’s plans to create two versions of the clock.
Burgess’s clock B was sealed in a clear plastic box and tested, overseen by the Worshipful Company of Clockmakers and the National Physical Laboratory. At the end of the 100-day trial, which ran from January to April 2015, it was found that the clock had lost just 5/8ths of one second throughout the trial. As a result, the Guinness World Records declared it "most accurate mechanical clock with a pendulum swinging in free air".
John Harrison memorial
John Harrison died on March 24th 1776 at the age of 82. He was buried in Hampstead, London but was memorialised in the nave of Westminster Abbey. His memorial stone bears the inscription John ‘Longitude’ Harrison Clockmaker 1693-1776 and is inlaid with a metal strip giving the longitude of the stone, 000º 7' 35" W, which was calculated by the National Maritime Museum.
Antique clocks for sale at Hemswell Antique Centres
While we may not have a Harrison Lesser Watch in our centres, we do have a fascinating selection of antique clocks for sale. Our antique clock dealers have the finest examples of antique wall clocks, antique longcase clocks and vintage mantel clocks. But don’t just take our word for it! Why not join us in person and spend a wonderful, indulgent day browsing our 4 expansive buildings on the site of the former RAF Hemswell? We look forward to seeing you soon.
