John Harrison and the Solution to the Longitude Problem - Page 2

Some of the great minds of the age advocated astronomical solutions. Galileo spent several years observing the moons of Jupiter. He asserted that eclipses of the moons of Jupiter occurred regularly enough to allow sailors to mark time by them, allowing sailors to ascertain their position. Unfortunately, the moons of Jupiter are difficult to see during the day and sometimes at night as well.

Other astronomers were fans of the lunar distance method, which used the distance between the moon and the stars to measure longitude. Initially, astronomers lacked the data to measure such distances. Royal Astronomers, including Neville Maskelyne, a staunch opponent of the mechanical method, soon remedied this. But even with the immeasurably helpful almanacs and data the royal astronomers had so dutifully collected, the mathematics involved and the precise observations required of sailors made the lunar distance method cumbersome.

The clockmakers began their work in earnest with a 1660 shipboard test of a pendulum clock built by Christian Huygens. Unfortunately, the pitching of the ship wreaked havoc on the mechanism. Temperature, pressure, and humidity variations were disastrous for clocks aboard ships.

Even if, by some miracle, all of those variables were held constant, winding and lubrication still posed problems. For many years, watches had a tendency to stop, slow down, or run backwards when wound. Obviously, such behavior would seriously limit the accuracy of a timepiece, but watches had to be wound—in an age before batteries, there was little alternative. Also, for many years, friction, the same force which automobile brakes apply to the wheels of speeding cars, threatened to slow down or even stop the gears inside a clock.

To avoid friction, clockmakers turned to lubrication. The lubricants they used, however, tended to change viscosity or thickness. This could slow or even destroy a clock.

With so much prize money at stake, the board received any number of other solutions to the “longitude problem,” from the impractical (fleets of ships at fixed positions across the ocean firing cannons) to sadistic (wounding a dog and applying at a fixed time in the home port a powder that could instantly heal his wound).

The “longitude problem” was finally solved by a man named John Harrison. Harrison was born in 1693 in Barrow, Lincolnshire, England, the son of a carpenter who taught him woodworking. As far as we know, John Harrison had no formal education. He built his first clock in 1713, making the moving parts out of a special wood that secreted natural grease and required no lubrication.

In 1737 he built his first marine clock. Over the next 33 years he built four more, each better than the one before. The first weighed 75 pounds. The last could be carried comfortably in a pocket.

Article Author: Brian Burns

Brian Burns holds a BA in Journalism from the University of Oklahoma and is now in Divinity school.

Visit Brian Burns's author page — Brian Burns's Blog