John Harrison's "H1" clock in action

John Harrison's "H1" was his first 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 "H1" clock, which is now in the care of the Royal Observatory Greenwich. John Harrison (https://en.wikipedia.org/wiki/John_Harrison) Longitude Rewards (https://en.wikipedia.org/wiki/Longitude_rewards)