The East-West Position Clock
Voice 1
Welcome to Spotlight. I'm Mike Procter. Voice 2
And I'm Liz Waid. Spotlight uses a special English method of broadcasting. It is easier for people to understand, no matter where in the world they live.
Voice 1
The year was 1707. The English ships were in heavy seas. The weather was bad, and they were lost. The chief of the ships was Admiral Shovell. His officers made an estimate of the ships' position. But they were wrong. Suddenly, someone shouted ‘Land!' This call filled the sailors with fear. There should be no land here. They were in the wrong place. Four of the ships crashed into the land. Over 1,600 men died that night. Only 26 survived. It was one of the worst British sea accidents in history. Today's Spotlight is on one unexpected result of this accident. Voice 2
At the time of the accident, England depended on the shipping industry. Ships brought the people of England sugar, spices, and tea. The people who sailed the ships needed good maps.
Voice 1
But they also needed something more. They needed to avoid accidents like the loss of Admiral Shovell's ships. To do this they needed to know exactly where they were. If you look at almost any map, it is divided into small squares by lines. The lines that go from east to west are the latitude lines. And the lines that go from north to south are the longitude lines. Sailors could estimate their north-south position, or latitude, easily. They could measure it from the sun and the stars. But they could not measure their east-west position, or longitude, by that method. They needed a good way to measure the ship's ‘longitude'. Voice 2
King Charles the Second of England knew how important it was to solve this problem. If the problem was not solved, more ships could be lost. In 1675, King Charles ordered the building of the Royal Observatory. The Observatory was a place where people could study the stars. They could work on the problem of establishing longitude at sea. The King created the Observatory in Greenwich. The first chief of the Observatory was John Flamsteed. Flamsteed worked hard, but he could not solve the longitude problem. And after the loss of Admiral Shovell's ships, there was even more pressure to find a solution. So in 1714 the British Government offered a prize of GBP 20,000. The prize would go to the first person who could find a method of measuring longitude at sea. Some people thought that this would never be possible.
Voice 1
Our story moves on, to one man - John Harrison. He was born in Yorkshire, England in 1693. He was 21 years old when the government offered the prize. Like his father, he was a carpenter. He made things with wood. He did not have much education. But John was very good at making clocks. At that time, all clocks were made from wood. But John made many improvements to the clock design. His clocks did not break, like other clocks. And his clocks were very accurate. Each month they lost or gained no more than one second. They were more accurate than many of the best clocks in London. Three of these clocks still exist. And they are still very accurate!
Voice 2
Harrison wanted to win the longitude prize of GBP 20,000.There was one simple way to estimate longitude. There are 24 longitude lines. At each line, the time changes by one hour. The simple solution was time! Sailors needed to know the exact time in two places. First, they needed to know the time in their own location. Sailors could use the position of the sun and the stars to tell the time where they were. But the sailors also needed to know the time at the place where the ship had started its voyage. The difference between the two would tell them their distance from that location. If they knew that, they could work out their east-west position on the earth's surface. Voice 1
The problem was that clocks at that time were not very accurate. They became less accurate when the air temperature changed. Movement could also affect a clock's accuracy. So could water. All of these caused problems for clocks on ships! But Harrison knew that he could make a clock that would keep time during a sea voyage. Such a clock is called a chronometer.
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It took Harrison five years to make his first chronometer. It performed well, but he continued to make changes to improve his designs. Some of these developments are still used in clocks and machines today.
Voice 1
Harrison's fourth chronometer was very different from the other three. It was much smaller. It looked like a large watch. Harrison's son William took the new improved chronometer with him on two trips to the West Indies. On both of these long sea trips the watch kept time very well - well enough for Harrison to win the prize.
Voice 2
However, a group of experts would decide who should get the prize. The group was called the Board of Longitude. And the Board was not satisfied with Harrison's clocks. Harrison was a carpenter. He had no education. The group wanted to make sure that Harrison had really made the watch. And they wanted to test it more, to make sure that it really worked. They asked Harrison to tell them how he had made it. At first Harrison was not willing to give away his secret. But in 1765, six experts visited Harrison and examined the watch. The Board gave Harrison only half of the prize money.
Voice 1
Harrison was now almost 80 years old. The Board still refused to pay him the rest of the prize money. So Harrison decided to appeal to the King, George III. The King tested the watch himself. He found it to be very good. The King soon agreed that John and William Harrison had been unfairly treated. But the Board of Longitude still refused to pay the money.
Voice 2
So in April 1773, John and William Harrison appealed to the British government. And the appeal was successful. John Harrison received almost all of his money. But it was the government, not the Board, who gave it to him. John Harrison died on the 23rd of March 1776. He had solved the longitude problem, for ships to find their east-west position. And he was finally recognized for his work.
Voice 1
The writers of today's programme were Shelagh Godwin and Mike Procter. The producer was Nick Mangeolles. The voices you heard were from the United States and the United Kingdom. You can listen to this program again, and read it, on the internet at http://www.radioenglish.net This .programme is called ‘The East-West Position Clock.' Voice 2
We hope you can join us again for the next Spotlight program. Goodbye.
