John Harrison's "H3" clock in action

Описание: John Harrison's "H3" was his third attempt at a clock that could survive sea-travel without losing time. This was in response to the "Longitude Rewards" (a challenge to develop a reliable system for determining Longitude while at sea). It was not accurate enough, so a another clock was attempted.

This is the original "H3" clock, which is now in the care of the Royal Observatory Greenwich.

John Harrison (https://en.wikipedia.org/wiki/John_Ha...)
Longitude Rewards (https://en.wikipedia.org/wiki/Longitu...)