If you're interested in the subject, the book "Longitude" by Dava Sobel (mentioned in Resources) is a very good read with lots of historical perspective on how these clocks were built.
Interesting features of John Harrison's sea clocks
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Re: Interesting features of John Harrison's sea clocks
#12Re: Interesting features of John Harrison's sea clocks
#13If you're interested in the subject, the book "Longitude" by Dava Sobel (mentioned in Resources) is a very good read with lots of historical perspective on how these clocks were built.
Made into a four-part mini-series with Jeremy Irons and Michael Gambon: * https://en.wikipedia.org/wiki/Longitude_(TV_series) * https://en.wikipedia.org/wiki/Longitude_(book)
Re: Interesting features of John Harrison's sea clocks
#14No wonder the Longitude Board gave him such grief. It must have seemed like he was deliberately trying to hide secrets from them. Unless you understood how important friction and temperature were in causing the drift of clocks at that time, it would have all seemed like unnecessary complexity.
Re: Interesting features of John Harrison's sea clocks
#15Example, one of the first results to come up:
https://www.core77.com/posts/25224/lignum-vitae-wood-so-bad-...
Re: Interesting features of John Harrison's sea clocks
#16Fascinated by "lignum vitae" mentioned several times. A little googling and I'm even more intrigued by this special wood. Example, one of the first results to come up: https://www.core77.com/posts/25224/lignum-vitae-wood-so-bad-...
Re: Interesting features of John Harrison's sea clocks
#17I had no idea that Harrison's clocks were so complex. His obsession with friction and changing conditions was clearly necessary, in retrospect , but WOW. The extensive use of "anti-friction" wheels, and even portions of a wheel, is very cleaver, but at some point the things look like he's trying to win the clockmakers version of an Obfuscated C contest[1]. No wonder the Longitude Board gave him such grief. It must ha…
Re: Interesting features of John Harrison's sea clocks
#18I had no idea that Harrison's clocks were so complex. His obsession with friction and changing conditions was clearly necessary, in retrospect , but WOW. The extensive use of "anti-friction" wheels, and even portions of a wheel, is very cleaver, but at some point the things look like he's trying to win the clockmakers version of an Obfuscated C contest[1]. No wonder the Longitude Board gave him such grief. It must ha…
It can't have helped that by all accounts he was extremely verbose in spoken communication, and almost impenetrable in written communication.
Re: Interesting features of John Harrison's sea clocks
#19Fascinated by "lignum vitae" mentioned several times. A little googling and I'm even more intrigued by this special wood. Example, one of the first results to come up: https://www.core77.com/posts/25224/lignum-vitae-wood-so-bad-...
Sadly it is an endangered species so it is illegal to trade now, I understand the best way to get it is to buy antique crown-green bowls and cut them up.
It's a wonderful and useful timber, it's a damn shame it's been necessary to add it to the CITES Treaty (as it's such a slow grower).
Re: Interesting features of John Harrison's sea clocks
#20This story surprised me because I'd have thought by now that Harrison's clocks would have been analyzed to the nth degree and copies of them made given their historical significance.
In recent years we've seen considerable efforts made in trying to reverse engineer the Antikythera mechanism so it's surprising a similar effort hasn't gone into a full understanding of these wonderful clocks, especially given that we have them both intact and in good combination.
It seems to me we should not only have a full mechanical understanding of these clocks together with a good rationale for why Harrison tackled the problem as he did but also that an x-ray fluorescence (XRF) analysis should be done on the metals used in their construction.
Assuming Harrison used the best materials available in the Eighteenth Century then an XRF analysis would give us a better understanding of the composition of those materials and of their production but also of the metrology methods in use in Harrison's time.