Greenwich and the story of time
|The first accurate chronometer|
The government's challenge
The British government received hundreds of applications for their challenge to invent an accurate device for measuring longitude at sea. Many were good ideas, so small cash grants were offered so that inventors, scientists and mathematicians could develop them into useful solutions.
A carpenter and clockmaker living in Lincolnshire called John Harrison made one of these applications.
Unlike the complicated ‘Lunar Distance’ method, scientists knew, in theory at least, that longitude could be found by using a portable timekeeping device.
Watches were invented 200 years before Harrison, but they were all too inaccurate to be of much use to a navigator. A well-made watch of the early 18th century might keep time to two or three minutes a day at best. What was needed to win the Longitude prize was an accuracy of two or three seconds a day!
The first chronometers
With funding from the Board of Longitude, the government body set up to oversee the longitude prize,
Harrison was still determined, and in 1750 made a breakthrough that would lead to one of the greatest inventions of all time. This was the first accurate portable timekeeper, what we now call a precision watch.
Harrison turned the way scientists thought about timekeeping on its head.
After dedicating his entire working life to the longitude problem, Harrison expected prompt and full payment for his invention. Unfortunately, the government was not so easily convinced, despite successful trials of the watch on journeys to both Jamaica and Barbados.
Four of Harrison’s experimental timekeepers can be seen today at the Royal Observatory.