Book Review: Longitude by Dava Sobel

I first heard about this some time ago as one of the best ‘popular science’ books of recent years. I spotted it in the same bookshop when I picked up Daniel Tammet’s Thinking in Numbers. It was somewhat shorter than I thought it would have been, but then my perception may be skewed by having only recently read Richard Holmes’ The Age of Wonder which may have spoilt me.

Sobel introduces us to the problem at hand, namely that of working out what your longitude is when at sea. It was comparatively easy to work out what your latitude is; this can be done with some astronomical/solar observations. However, if you are on the equator, then to sail east or west by one degree of longitude will entail travelling further than if one is sailing at a constant latitude of, say 30 degrees. Though in so doing, Sobel does betray a lack of understanding of spherical geometry by stating that sailing on a line on constant latitude yields the shortest route west, instead of following a great circle.

The book then focuses on the work of John Harrison who thought the best way to solve the problem was with accurate timepieces that could be kept on board ships at sea. He was not without his rivals, though, with some convinced that further astronomical measures would avoid the need for accurate clocks. Yet the overriding sense one gets is that there was an institutional snobbery  which Harrison was subjected to as he attempted to prove to the relevant authorities that his work was up to the task.

In so doing, Sobel avoids much of the science after having fumbled a little bit at the start and the rest is much more “pure” history. That left this reader a little frustrated, not least because I had heard such high praise for Longitude. As it is, it’s interesting enough but did not capture my attention as I had hoped it might. So it’s a pleasant enough read with some interesting aspects of history noted that I was previously unaware of, but it’s nowhere near as fine as The Age of Wonder. For anyone interested in the history of science, it is one to put on the reading list, but there is no need to unduly rush into reading it straight away.


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