While dismantling John Harrison’s pioneering clock Jonathan Betts found evidence he did not work alone as is usually assumed. He also uncovered hidden features like this decorative bird deep inside the mechanism – check out this gallery to see more.

The story of John Harrison the “lone genius” who solved the problem of finding longitude at sea is in urgent need of a rewrite.

Discoveries made during repairs to Harrison’s first successful “sea clock” – completed in 1735 – suggest that others contributed to his pioneering timepieces. “Harrison is always cast as a self-taught lone genius pitted against the establishment. The truth is, that is a great over-simplification,” says horologist Jonathan Betts of the Royal Observatory, Greenwich, London.

Betts dismantled the device – called H1 – after it stopped last year when a connection between a spring and a swinging balance broke. “It’s only when you take it apart and have it in your hands that it comes home to you: the story isn’t quite the one that’s told.”


See a gallery of images of H1 that show what Betts found.

Longitude legend

The John Harrison legend, made famous in 1995 by Dava Sobel’s surprise bestseller Longitude, has the country carpenter-turned-clockmaker designing and building a series of innovative timepieces that kept near perfect time on long sea voyages – without any advice or help from others.

At the time, mariners were unable to calculate longitude accurately and hence could not pinpoint their position at sea. Harrison’s fourth marine timekeeper – H4, a watch rather than a clock – became the first to qualify for the £20,000 offered by the British Government to whoever cracked the problem, although he spent decades fighting for his money.

Now Betts has uncovered evidence that Harrison was not the lone pioneer the legend would have us believe. While carefully taking apart the 1500 components that make up H1, he has found signs that the provincial craftsman may have had help from more experienced clockmakers to make some of the more sophisticated parts.

Lost and found

H1 hadn’t stopped since being cleaned in the early 1960s and Betts is only the third person to have taken it apart since Rupert Gould, who in 1920 discovered the three large timekeepers H1, H2 and H3, broken and mouldering behind a cabinet at the Royal Observatory.

Gould spent years repairing and recreating broken and missing parts – and it was one of his replacement parts that stopped the clock in late 2008. A thin steel strip that connected one of the clock’s springs to a swinging balance had rusted and snapped (see the broken part).

“Gould’s repair lasted 80 years, which isn’t bad, but there are no signs of any wear on Harrison’s parts,” says Betts. Harrison famously designed his clock so that there was no friction between moving parts and it never needed oiling.

Hints of help

While studying the dismantled masterpiece Betts came across features that suggested Harrison’s legend is not quite accurate. “It’s always said that he made the parts alone [in rural Lincolnshire] – except for some help from his brother. But when you look at it, that doesn’t quite add up.”

For example, H1’s brasswork is too impressive to fit with the legend. “The received wisdom is that Harrison transferred his considerable woodworking skills to brass but working brass requires different skills,” says Betts. He may have learnt the techniques by studying expert brassworkers but H1 – his first brass clock – doesn’t bear the hallmarks of a beginner, suggesting he probably commissioned someone else to help out.

Neither were H1’s dials all Harrison’s work: the reverse of each bears the words “upwards” – an instruction to the engraver. Another clue lies in the fusee mechanism, which evens out the pull of the mainspring.

At the time, even the best clocks made in London had fusees wound around with a cord of gut rather than a chain, says Betts. But H1 used chain and was one of the earliest clocks to do so. In fact, it has two fusee chains, each a metre long with each link in five parts, needing up to 2000 components for each chain.

‘Specialised skill’

“Making them was a very specialised skill, and they were mostly fitted to watches,” says Betts, “That’s so sophisticated, I find it hard to believe he made this in Barrow on Humber as a loner.”

He thinks the chains were bought in London and believes that Harrison watched craftsmen at work there, asked their advice, and commissioned their help. “There was definitely more involvement from other people. What we don’t know is how far it went. People thought he just sat down and made it all by himself. It was surely not like that.”

Betts has now made a new, non-rusting repair that should last longer than Gould’s. “I’m also doing a bit of light dusting, which is more important than it sounds,” he says. Although H1 shows no wear, it suffers from what Betts calls “computer mouse syndrome” – the accumulation of compacted fluff that eventually jams the rollers in older mechanically operated mice.

One of Harrison’s innovations to avoid friction was to make parts roll over each other with minimal contact, avoiding the need for oil. “On those parts fluff is mashed to crud and has to be gently scraped off,” says Betts.

See a gallery of images of H1 that show what Betts found.