Harrison | John | 1693-1776 | horologist

Biographical Information

Occupation, Sphere of Activity

John Harrison (1693-1776), winner of the Board of Longitude's prize, probably inherited his interest for horology from his father, a carpenter by trade, who occasionally repaired clocks. Harrison never had a good education, and it is said that he never learned to express himself well in writing.

His first clock was built in 1713, and much of his early work was built in collaboration with his brother, James. Together, they revolutionised clock design by completely eliminating the need for lubrication. Until then, poor clock oil had been one of the largest causes of clock failure. John Harrison also invented the gridiron pendulum, made of alternate rods of steel and brass, whose relative dilations cancel each other out when the pendulum is heated. This meant that warm weather no longer made clocks run slow. Timepieces equipped with the gridiron pendulum were superior in accuracy to the best clocks of the day. Around the same time, he also introduced a second spring into clocks, to keep them running while they were being wound up.

Knowing of the Board of Longitude's series of prizes for finding methods of measuring longitude - including the top prize of £20,000 for finding it accurate to within 30 miles, Harrison adapted his techniques to build a series of clocks which would remain accurate at sea, where waves would make traditional pendulum clocks erratic. The time shown on the clock could then be compared with the local time, which could be ascertained from astronomical observations, to find the position's longitude. His fourth clock, which finally won the prize, was a massive improvement on other clocks of the day. It was also considerably smaller than anything he had built before, looking more like a large pocket watch, 13cm in diameter and weighing 1.45kg. During a four month voyage to Jamaica in 1761-1762, it lost only five seconds - which translates as 18 miles accuracy, well within the limit for the top Longitude prize. On a later journey, the inaccuracy was reduced further.

However, hostility from certain members of the Royal Society - who hoped to win the prize themselves - led to extra hurdles being placed in Harrison's path, including more, lengthier tests, demands of several more prototypes and the surrender of his creations and their designs to the government. Even after these obstructions were cleared, the Board remained reluctant, and it took the intervention of the King and Parliament for Harrison to get his prize. This only happened in 1773, nearly twelve years after he had fulfilled the original conditions, and only a few years before his death.


Harrison's early work was carried out in collaboration with his younger brother, John Harrison

Other Significant Information

Notable publications:

An Account of the Proceedings in Order to the Discovery of the Longitude (1763)

A Narrative of the Proceedings Relative to the Discovery of Longitude at Sea (1765)

The Principles of Mr. Harrison's Timekeeper, with Plates of the Same, Published by Order of the Commisionners of Longitude (1767)

A Description Concerning Such Mechanism as will Afford a Nice or True Mensuration of Time, Together with some Accounts to the Discovery of the Scale of Music (1775)

Interests and activities:

Harrison had an interest in music and sound. He carried out a number of experiments on this subject, and invented a new division of the musical scale.

Honours, Qualifications and Appointments

1749: Awarded Copley Medal of the Royal Society

1773: Awarded the Prize of the Board of Longitude


List of sources for the biographical information:

Royal Observatory, Greenwich, John Harrison and the Longitude Problem, ( http://www.rog.nmm.ac.uk/museum/harrison, 1999)

University of St Andrews, English Attack on the Longitude Problem, ( http://www-history.mcs.st-andrews.ac.uk/history/HistTopics/Longitude2.html, 1997)

Lee, Sidney, Dictionary of National Biography, vol IX, (London, Smith, Elder & Co, 1908)