So I’ve just finished Longitude by Dava Sobel, a great history of the struggle to create a reliable method of calculating longitude. It was a quest that lasted for hundreds of years, fuelled by rivalry, prejudice, discovery and war (also, a smidge of science).

Lines of latitude and longitude began crisscorssing our worldview in ancient times, at least three centuries before the birth of Christ. By A.D. 150, the cartographer and astronomer Ptolemy had plotted them on the twenty-seven maps of his first world atlas.

But while it’s easy to take a ruler to a map, orienting yourself on that map is another problem entirely. Especially so at sea, where landmarks are scarce. Lacking a way to devise longitude, countless lost their lives to navigational mistakes; shipwrecking or becoming hopelessly lost.

Luminaries from Galileo to Isaac Newton and Robert Hooke, as well as countless in between, worked to find a solution. Some were brilliant, if impractical – deriving longitude from the moon and stars; some were plain bizarre – a combination of magic powder and injured dogs.

In the end it came down to time. If you know the exact time where you are, as well as at your point of origin, longitude is child’s play to calculate. But creating an accurate timekeeper in the steampunk age, let alone one that holds up to a battering at sea, defied the best minds. In the end it was an uneducated carpenter named John Harrison who solved the problem.

He changed the world.

Some modern horologists claim that Harrison’s work facilitated England’s mastery over the oceans, and thereby led to the creation of the British Empire — for it was by dint of the chronometer that Britainnia ruled the waves.

But the thing that has really played on my mind over the past couple of days is not this “big history” aspect. Rather, Harrison and his clock marks the end of being without time. Our lives are so regimented now, everything on a schedule. And that’s before we even consider the important timekeeping continues to play in making our world smaller – through its use in GPS for example.

Harrison extended rigorous timekeeping beyond cumbersome and stationary pendulum clocks, invented parts that can still be found in modern clocks, and brought time to the waves. It was through Harrison that time conquered the world.

With his marine clocks, John Harrison tested the waters of space-time. He succeeed, against all odds, in using the fourth-temporal-dimension to link points on the three-dimensional globe. He wrested the world’s whereabouts from the stars, and locked the secret in a pocket watch.

I really recommend Sobel’s book. It’s well written and fascinating account.