John Harrison's clocks helped sailors find longitude accurately.
John Harrison's clocks helped sailors find longitude accurately.
BOB DOUGHTY: While scientists were studying the stars and moon to solve the longitude problem, a man named John Harrison was working on another project. He was trying to build a clock that would help sailors learn longitude.
His task also was difficult and complex. Mister Harrison had to develop a clock that was not affected by the movement of a ship on the ocean or changes in temperature or atmospheric pressure.
He began developing his clock in seventeen thirty. It took five years to complete. The complex device weighed thirty-four kilograms. Several years later, Mister Harrison built a second clock. It was smaller, but weighed more than the first. Mister Harrison was not satisfied and began working on yet another device.
Twenty years later, he completed a device that was smaller than the first two, and weighed less. But still Mister Harrison was not satisfied.
Two years later, in seventeen fifty-seven, he produced a small clock that he could hold in his hand. The clock could tell the correct time in two places, meeting the requirements for learning longitude on the sea.
STEVE EMBER: For many years after Mister Harrison's work was completed, the idea of using a clock to learn longitude was rejected. However, that opinion changed when manufacturers learned how to make better and less costly versions of Mister Harrison's clocks.
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2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25
2013-11-25