John Harrison and the Solution to the Longitude Problem - Page 3

Harrison’s clocks sported a revolutionary friction-free mechanism and a variety of metals that complemented each other so that as one part expanded with the temperature, its mate contracted. As for winding, required every thirty hours or so, the operation of Harrison’s watches was largely unaffected by it. His final watch lost less than half a second a day, even aboard ship.

Along the way, Harrison’s notes were confiscated, his secrets revealed, and his creations tested by his archnemesis, the Royal Astronomer, Neville Maskelyne. In 1764, Harrison was also required to surrender to the Board all of his marine clocks and then to build, from memory, two replicas of H-4, the fourth of his sea clocks. Only these two replicas would suffice to prove to the board that Harrison’s method was “practicable and useful” as the bill demanded.

The events of the spring of 1765 were to prove pivotal in Harrison’s quest for the longitude prize. At that time Parliament passed a new law that added more requirements for winning the prize. Harrison is named explicitly in the bill.

The first of the replicas the board required, Harrison’s final watch, was completed in 1770 and named H-5. Harrison was 77.

By this time, Harrison had made at least one powerful friend—King George III. King George personally tested H-5 at his personal observatory at Richmond in the summer of 1772. The watch performed splendidly, after some initial problems which were solved when a magnet that had been left in the testing room was removed.

In 1773, the Board of Longitude discussed the Harrison case for the last time. Two members of Parliament were present this time, and after a passionate appeal form Harrison, they granted him a bounty through the benevolence of Parliament. The Board declined to award Harrison the actual prize.

In fact, the conditions for winning the prize were changed in 1773 to include a stipulation that two of any timekeeper vying for the prize be submitted.

John Harrison died in 1776. The longitude prize was never claimed. The Board of Longitude was dissolved in 1828.

For a more thorough treatment of “the longitude problem” I recommend Dava Sobel’s Longitude, an excellent book that proved very useful in the preparation of this article.

Article Author: Brian Burns

Brian Burns holds a BA in Journalism from the University of Oklahoma and is now in Divinity school.

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