Science Museum

Here you can see the story of JOHN HARRISON (1693-1776) and THE CHALLENGE OF LONGITUDE.

The need to be able to calculate longitude at sea became so acute by 1714, that the British Government offered a prize of £20,000 for a solution. An accurate marine clock was thought by some to be the answer and the prize precipitated a surge of interest in scientific horology throughout Europe. The solution was found in London by the century's end.

Mariners had no means of finding their longitude at sea. Terrible disasters resulted. In July 1714, the British Government offered a substantial prize for a solution. The main contenders were those who thought that longitude could safely be found only bs astronomy and those who believed that clocks could provide the answer.

In theory, if a chick is set to local une at a hour port and maintained accurately, a navigation simply has to check the time where he is (by observing the heavens) and compare it with home time (as shows by the clock). The time difference will reveal number of degrees east or west of home the ship had travelled.

In practice, the best land fued timekeeper, the pendulum, would not work at sea. Many other problems related to temperature, motion, corrosion, friction and lubrication had to he overcome. Numerous attempts failed, including that by Henry Sully, a freeman of the Clockmakers Company in the 1720's.

John Harrison, whose lifetime of experimentation brought him from Lincolnshire to live in London, eventually won the prize. His fourth marine timekeeper and his fifth (displayed here) changed the world. These spectacular instruments were made in Red Lion Square.

Pascal Brackman