Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time

Good non-fiction answers a question you hadn't thought to ask. I had not realized how difficult it was to measure longitude. This short book details the scientific and political struggle of John Harrison, a British clockmaker. Although a volume of this size or much greater could explain the intricacies of clock mechanisms, this volume doesn't particularily do that. It does show how Harrison had to fight the entrenched scientific idea that longitude could only be found using astronomy.

Indeed, before Harrison, that was the case. On land longitude was measured using telescopic readings of Jupiter's moons. At sea, however, telescopes couldn't hold an image long enough to be accurate. Harrison's clocks attempted to measure the difference between a ship's port time and the local time. This works because one hour of longitude is actually one twenty-fourth of the earth's daily rotation. Before Harrison, nobody had built a clock sturdy or accurate enough to use for navigation.

British Parliment came up with the Longitude Act, a sort of early request for proposals, that would reward the winner with a large cash prize and fame. The prevailing academic notion was that the Moon's cycles could be used to cipher longitude. This was pushed by Isaac Newton, and a host of other astronomers who thought mechanical solutions were too fragile. But the moon is not visible behind clouds, during the day, and when it's obscured by the earth. Furthermore, the moon-method required at least 45 minutes of calculation by a ship's navigator.

Despite the political pressure not to use mechanical clocks for navigation, Harrison's worst enemy was his own perfectionism. His dealings with the Board of Longitude (the people in charge of awarding the prize) were tumultous largely because of how he dispariaged his own craftsmanship. Regardless, the H-4 (also known as The Watch) was a masterpiece of timekeeping that demonstrated extreme precision and ease-of-use.

*Cross Posted from A Single Step*