Sobel ranks right up there with Mark Kurlansky for writing detailed, fascinating accounts of historical technology. Calculating longitude had bedeviled mariners for centuries. To do so required an extremely accurate timepiece.John Harrison thought he could solve the problem. The book is a nice combination of science and biography. It reminded me of another similar work Noble Obsession Charles Goodyear, Thomas Hancock, and the Race to Unlock the Greatest Industrial Secret of the Nineteenth Century which details Goodyear's lifelong attempts to discover the secrets of vulcanization.
The search for an answer was given a push when Parliament offered a huge prize for anyone who could find a way to calculate longitude accurately. A big problem was figuring out a way to overcome errors induced by humidity causing the pendulum to swell or cold making it contract. Both these effects would through off its balance inducing time-keeping errors.
I have to admit admiring the tenacity and single-mindedness with which both Goodyear and Harrison attacked innumerable problems, never giving up. It's a shame that both had to overcome non-technical personal, social, and political problems to reap any rewards for their efforts.
