18th-century clockmaker John Harrison vindicated by ‘perfect clock’

Source: Telegraph

Three centuries after he claimed his clock could solve the problem of longitude, proof John Harrison’s design is accurate to the second for 100 days

A clock based on an 18th-century design has stunned experts by keeping accurate to a second after 100 days – just as its maker promised 300 years ago.

John Harrison built a clock with the intention of solving the problem of longitude at sea, but was ridiculed by his contemporaries.

A modern-day clock based on his design has now been certified by the Guinness World Records after it neither gained nor lost more than a second during a 100-day test.

The Martin Burgess Clock B was part of the trial at the Royal Observatory in Greenwich, where it stunned experts by keeping perfect time.

Rory McEvoy, the Observatory’s curator of horology, described the design as “something approaching a perfect clock”.

Harrison, who was the subject of Dava Sobell’s bestselling 2005 book Longitude, had boasted that his revolutionary clock would neither lose nor gain more than a second in 100 days. Last Thursday morning his claim was shown to be entirely accurate.

The National Maritime Museum confirmed the record on Twitter, writing: “Our 100 day trail of ‘Clock B’ won @GWR for ‘most accurate mechanical clock with a pendulum swinging in free air’!”

Jonathan Betts, a member of the Antiquarian Horological Society, said: “As soon as we set the clock running it was clear that it was performing incredibly well, so then we got the case sealed because nobody was going to believe how well the clock was running.”

He added that the clock was not a replica of Harrison’s, but used his design and concept.

‘It is important to realise his design goes against everything the establishment has claimed is the best throughout history,’ Mr Betts told the Independent on Sunday.

Harrison, the original designer, created his first clock in 1713 – during a time when many Royal Navy ships were being lost at sea.

It was considered such a significant problem that Parliament offered rewards of up to £20,000 to anyone who could solve it.

Harrison’s contemporaries argued that a heavy pendulum bob and short swing would be the best. But he dismissed their theory and claimed that a clock with a lighter pendulum bob and wide swing would work better.

He claimed his design, which was the basis of the Martin Burgess Clock B, would solve the problem of determining longitude at sea.

Sailors would be able to determine longitude accurately, he claimed, by knowing the amount of time the ship had been at sea and the local time by using the sun.

Local time is one hour ahead for every 15 degrees of longitude east and one hour behind for every 15 degrees of longitude west.

Harrison was not taken seriously by any of his rivals and the possibilities of his clock were not explored until the 20th century.

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