Longitude

A watch is a commonplace item in the modern life, but in the 18th century it played a great role in preventing ships from getting lost in high seas. Known as The Longitude Problem, there was no practical means to ascertain longitude at sea which prompted the British parliament to set up the Board of Longitude to administer a prize for anyone who could determine longitude at sea.

The solution came from an unexpected quarter - a carpenter named John Harrison took it up on himself to build a watch so accurate that it could withstand the vagaries of the sea's conduct. His watch names H4 became a masterpiece of keeping time and helped the British Empire conquer the sea. Despite it's success there was a fierce competitor - The Sextant. This device was able to tell longitude by measuring the distance between celestial bodies and the sea's horizon. While dependable, it required training and took many hours to make a reading.

This book is about the huddle that John Harrison had to jump in order to win the Longitude prize money of 20,000 pounds and ensure his innovation becomes the de-facto instrument for measuring longitude at the sea.