Harrison, John

Harrison, John (1693-1776), clock maker, b. Foulby, Yorkshire, England.

John "Longitude" Harrison made the first chronometer, which is an instrument to measure time extremely accurately.

In his day, an instrument of this kind was wanted by sailors. They needed to know the exact time in order to work out their longitude.

For his invention Harrison was awarded a prize by the British government.

Captain Cook took one of Harrison's chronometers on his voyage of 1772-75. After three years at sea in hot climates, it was found to be only 7 minutes 45 seconds fast.

See Dava Sobel Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time