The book I’m slowly swimming through, shaping Time, is slow work because it keeps making me think of other things it highlights.
Like the fact that accurate astronomy was known by the ancients, almost 2,000 years ago, but for most of European history, sailors relied on deep local knowledge and guess work. If they used astronomy, it was generally the moon which told them of tides. Why the long time?
Navigation began to be a big issue from about the mid 16th century, the great age of exploration. Why then?
Maybe the weather. the long ice age caused a lot of hunger, so people had to go further for food, so did sailors also go further afield? did Europeans become more dependant on sea food than the frozen fields?
It was also the time of the Reformation, which also may be related to the weather, with Christianity failing to explain the harsh time so may people were having. But the reformation also closed a lot of monasteries, so the knowledge of astronomy held there was lost, or was it recognised by some of the literate gents, and saved? The priests were heavily land based; their knowledge of agriculture was impressive, but they were not mariners, so they did not apply their knowledge to shipping. Did the Reformation encourage people to investigate practical astronomy for the first time, eventually bleeding down to the commonest of mariners, bringing about the navigational and exploration that was just as revolutionary as the more famous agriculture and industrial ones? By the early 18th century, there was a plethora of fine instruments for captains and as the Royal Navy expected its captains to provide their own instruments, they became economically viable. Harrison’s longitude clock was just one of many precision and less precise instruments that helped sailors find their way safely home. Early sailors had made do with error prone maps as they generally returned the same way they went out, so the errors were the same.