In this blog post, the author shares their experience of seeing John Harrison’s sea clocks at the Royal Observatory in Greenwich. They explain that Harrison solved the problem of calculating longitude at sea using a clock, despite facing challenges and opposition from the Board of Longitude. The author points out the porosity in some of the clock’s brass plates and speculates on the availability of high-quality materials during Harrison’s time. They also highlight the use of anti-friction wheels and lantern pinions with rollers in the clocks. The author finds the temperature compensation mechanisms difficult to understand and mentions an interesting feature on one of the clocks where stationary pillars stand between the spokes of the balance wheels. They provide a list of resources for further reading on John Harrison and his clocks.
https://incoherency.co.uk/blog/stories/harrison-clocks.html