A True Clockwork Expert

More than two hundred and fifty years ago — so long ago that America was still a collection of diverse, squabbling colonies — a British carpenter and clockmaker named John Harrison made an outlandish claim.  He contended that he had designed a pendulum clock that, if wound properly and in timely fashion, would keep time so accurately that it would lose only one second of time over a 100-day period.

clock_3272964b.jpgYou would think that Harrison’s claim would have had some credibility, because he had just invented a device that had solved one of the knottiest problems confronting the British Empire of that day — namely, allowing sailors to figure out their longitude on long sea voyages.  Latitude could be determined by looking at star charts and comparing constellations to the horizon, but longitude posed a seemingly impossible problem.  Harrison solved it by creating the chronometer, a device that kept remarkably precise time calculated from Greenwich, England.  By determining the local time, such as high noon, and then comparing it to the Greenwich time kept by Harrison’s clock, sailors could calculate how far away they were and determine their longitude.

But even though Harrison had solved the longitude problem, and won a large prize from the British government for his ingenuity, his claim to be able to build such an accurate pendulum clock was met with churlish derision.  Harrison was ridiculed, his claims were said to involve “an incoherence and absurdity that was little short of the symptoms of insanity,” and his clock design was forgotten for centuries.  But Harrison’s achievements became the subject of interest again in the 1970s, and a clockmaker attempted to decipher Harrison’s plans for the clock and build a replica.

Harrison’s design, called simply “Clock B,” then was tested, and the test results confirmed that Harrison was right all along.  During its carefully controlled 100-day trial, Clock B lost only 5/8 of a second when measured against official Greenwich time, and it was declared by Guinness World Records to be the “most accurate mechanical clock with a pendulum swinging in free air.”  Centuries after his death, Harrison was vindicated:  he was right, his critics were wrong, the design of Clock B was an amazing accomplishment for a clockmaker who lived during the mid-18th century,

It just goes to show you — sometimes the conventional wisdom isn’t wisdom at all.

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