Three forces contributed to the modern invention of time. First, the conquest of foreign territories across the ocean required precise navigation with accurate timepieces. Second, the invention of the railroad required the standardization of time across countries, replacing the local system of keeping time using shadows and sundials. Third, the industrial economy necessitated new labor laws, which changed the way people think about work.
1. The Emperor’s New Clocks
The history of timepieces is a history of empires.
Long before the modern clock used springs and familiar markings, just about every great civilization had attempted to measure time, with each one failing in its own special way. In ancient Egypt, China, and Mesopotamia, sundials, or “shadow clocks,” all required bright sunlight to count the hours, which wasn't of much use on overcast days. To work around this problem, some of these ancient civilizations used a “water clock,” or clepsydra, a device that steadily dripped water through a small hole into a container with lines painted around the side to represent the passage of time. But slight changes in temperature could change the viscosity of water and the rate of drips. On a cold day, the water might freeze, and so would time.
The most important breakthroughs in the history of horology required the incentives and resources of a global empire. Toward the end of the Exploration Age, the great powers like England, France, and Spain struggled to navigate the oceans, because they couldn’t accurately measure longitude, or their progress east or west of their site of departure. As a result, they would crash into rocks or get lost and run out of food.
To some, this seemed like a problem of orientation. To John Harrison, an English carpenter, it was clearly a problem of time. Imagine that a ship departs from London for Jamaica with two clocks. The first clock keeps perfect London time throughout the journey. The second clock is reset to noon each day on the ocean when the sun reaches its highest point in the sky. As a result, the time difference between the two clocks grows as the ship sails toward the Americas. As you know, the earth rotates 360 degrees every 24 hours. That means 15 degrees every hour. So, for each hour that the two clocks were apart, the ship had traveled 15 degrees west—or about 900 nautical miles, which is roughly the distance between New York City and Missouri; a time zone.
The scenario above isn’t a hypothetical; it’s precisely the calculation that Harrison made. The subject of the classic book Longitude by Dava Sobel, Harrison became famous for building the two most advanced clocks (technically: chronometers) of all time. His timepieces didn’t rely on the dripping of water, flow of sand, or even the swinging of heavy pendula. They were precise and durable enough to withstand the ricketty journey across the ocean. For his pains—he spent about 30 years designing and tweaking the timepieces—he won a luxurious prize from the British government.