Time for a Sea Change

 
On March 24, 1693, English clockmaker John Harrison was born.

As England’s maritime exploits, explorations, and economy grew, the country’s mariners had run smack up against a seemingly impenetrable wall. They required convenient and accurate measure of their positions at sea, specifically their longitude, how far east or west they were of their port of call or even their home port. The equipment they used was cumbersome, useless on heavy seas, or under clouded skies. Ships and cargoes disappeared from time to time; fortunes and men lost. In one maritime disaster, four naval ships sank against the rocks off the Scilly archipelago with the loss in life of 800 men including the Commander-in-Chief of the British fleets – the navigators had been unable to calculate their longitude correctly. Safety and security at sea became a national imperative.

Parliament offered a reward to the person who could discover longitude to specific degrees of accuracy. No less a figure than Newton predicted that such a device could not be made to find longitude since, the finding, it must overcome the ship’s motions, differences in heat and cold, humidity and dryness, and various gravities. Newton never met John Harrison.

Harrison had a passion for clocks, for the gears and escapements that could make a time-telling device of great precision. He had taught himself how to make and repair clocks of every kind. He learned about mechanics and physics at public lectures. Usually he improved the clocks he touched. He improved pendulum accuracy. He invented his own “grasshopper” escapement, a device that released a clock’s driving power step-by-step while producing almost no friction and requiring no lubrication. He entered the longitude competition.

It took Harrison 45 years from start to finish of the final payout of the £20,000 (comparable to $4,000,000 USD) prize. Although his very first prototype filled the bill, longitude board members nitpicked, niggled, and piled on new “needs”. Harrison was a perfectionist and continued to refine his masterwork taking the various version and models through time and sea trials. He made several marine timepieces – the first three were accurate, box-style mechanisms; the fourth (considered the first of precision watches); and a fifth. No less a naval giant than James Cook used Harrison’s chronometer in his marine mapping. It took King George III’s loss of patience on Harrison’s behalf for Parliament to pay up. By that time, Harrison was 80 years old.

With his marine chronometer, Harrison had solved the greatest scientific problem of his day. He invested his passion, skills, and talent into an extreme commitment. The story of Harrison’s guts and glory has inspired every following generation, each of which has built upon his example of learning which aspects of the Sciences to accommodate and apply to accurate geopositioning devices.
 
In The Clock That Changed the World – a behind-the-science peek at the workings of John Harrison’s marine chronometer– scientist, historian and broadcaster Adam Hart-Davis presents hand-crafted wood surprises, captures grasshopper escapement, explains the complex problems of Harrison’s age, and even demonstrates location by triangulation with a stopwatch from a rowboat.

 

B Bondar / Real World Content Advantage

 

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