In the days before quartz crystal clocks one of my jobs as third mate of an ocean-going tramp was time officer. Whenever the old man decided to flog the clocks for a new time zone I had to go around and alter the hands of every clock in the ship except the chronometer. The chronometer was my responsibility. It was kept in a locked cabinet on the bridge and only the captain and I had a key. I had to wind it every day after receiving a radio time signal at noon Greenwich mean time. I recorded any divergence from GMT in a book and analysed the rate of change . The rate could change depending on variations in temperature as the ship steamed northwards or southwards.
The chronometer was the most important instrument on board. Without the chronometer shipwreck was a real possibility. It was the only means of determining the ship’s longitude. For many centuries sailors had been wrecked because they didn’t know where they were, with only Sun, Moon and stars to guide them. The problem came to a climax in 1707 when four British warships were wrecked on the west coast of England with the loss of about 2000 men; one of the worst maritime disasters in history.
The British government were so enlivened by this event that they offered a huge prize for anyone who could solve the problem of longitude at sea. An amateur clock-maker named John Harrison won the prize but he had to fight to actually collect the money, and then only got part of it. Dava Sobell’s book Longitude tells the story.
The mystery of time has occupied the rest of my life. Saint Augustine in the Middle Ages asked himself “What is time? If nobody asks me I understand time but if someone asks I cannot explain it to he who asks.”