John Harrison

His second marriage was with a woman, also named Elizabeth. This marriage lasted 50 years and produced two children. His son William assisted his father in designing and developing clocks and watches.

He died on his 83rd birthday in 1776.

He was born as the son of Henry, a carpenter and his wife Elizabeth. The oldest of five siblings, he assisted his father in his carpentry work.

He fell ill with smallpox as a child and was given a watch to amuse himself. Thus began his fascination with clocks and he would often tinker around with old clocks and study their mechanisms. He also loved music as a youngster.

Harrison was largely a self-taught clock maker; there are no records of him ever getting trained under a clock maker. He began building clocks quite early on with the help of his younger brother, James. The brothers built their first clock in 1713, and went on to build two long case grandfather clocks in 1715 and 1717.

In 1720 he built a clock for the tower of a local manor house. He built the parts requiring lubrication with a tropical hardwood that naturally oozes its own oil and thus would not require any other form of oiling.

His carpentry skills proved to be very useful for clock making too. He used oak and lignum vitae to make the wooden movements in clocks. He also developed the grasshopper escapement to improvise the quality of clocks.

Along with James he made at least three pendulum clocks between 1725 and 1728. He designed the grid-iron pendulum during this time. His precision pendulum clocks are considered to be the most accurate clocks of his time.

The British Parliament had announced a prize of 20,000 Pounds for a practical method determining a ship’s longitude in 1714; it was administered by the Board of Longitude. Even by 1730 no one had yet claimed the prize, so Harrison traveled to London to build an instrument for this purpose.

He invented the marine chronometer—a clock that precisely determines longitude by means of celestial navigation. It was a major technological development of the 18th century that took him more than three decades of hard work to achieve.