Harrison, John (1693-1776) English Horologist (Scientist)

John Harrison was a working-class carpenter who rose to fame as a horologist by designing and building a succession of clocks, the last of which was capable of keeping its accuracy well enough to navigate ships through cross-oceanic voyages. Harrison spent the majority of his years at work on the problem and then spent numerous years convincing the British government to grant him the prize it promised for the proper solution. Harrison revolutionized sea-travel, allowing sailors to navigate more accurately than ever (while also keeping good time)!

Harrison was born in 1693, at Foul by, in Yorkshire, England, and baptized on March 31 of that year. His father, Henry, was an estate carpenter and surveyor who moved the family to Barrow-upon-Humber. When Harrison contracted smallpox at the age of six, his parents set a watch on his pillow for its ticking to keep him company, and it also peaked his horologi-cal interest.

Harrison received little formal education, but he followed his father’s footsteps into carpentry, while also indulging his interest in timepieces by constructing his first at the age of 20 in 1713, a longcase clock made almost entirely of wood that now resides in the collection of the Worshipful Company of Clockmakers in Guildhall.

In 1714, the British Parliament announced what became known as the "Queen Anne Act," which offered a 20,000-pound prize (the equivalent of one million pounds now) for the solution to the "longitude problem," establishing the Board of Longitude to administer the submission of answers. The problem: sailors at sea could not calculate their longitude accurately without knowing the local time, which in practice required them to know a reference time— namely, Greenwich Standard Time. But no existing clock could keep accurate enough time while also withstanding the vicissitudes of temperature and humidity as well as the rolling waves at sea. In order to win the prize, the solution would have to keep the ship within half-a-degree (30 minutes in longitude, or two minutes in time).

In 1718, Harrison married his first wife, Elizabeth, who gave birth to their son, John, a few months later. Elizabeth died in May 1726, and by November of that same year, Harrison had married again—to another Elizabeth. Together, they had two children—William, born in 1728, and Elizabeth, born in 1732. By now, Harrison and his youngest brother, James, were gaining a reputation for their quality clock making. They designed a bimetallic pendulum clock, with the different coefficients of expansion of brass and steel rods maintaining a constant length (a swing-rate) for the pendulum. The team also constructed a turret clock at the Brockles by Park stables that required no lubrication, a radical innovation.

In 1728, determined to "find the longitude" (a disparaging term applied to those foolish enough to try for the prize), Harrison traveled to London, where his design so impressed George Graham that this renowned horologist loaned Harrison the funds to construct his proposed clock. From 1730 through 1735, Harrison constructed H1, as it is now known, a clock completely counterbalanced so as to run independent of the direction of gravity. In 1736, on a trial trip to Lisbon on the Centurion and back on the Orford, the ships would have sailed off-course if not for H1′s accuracy. However, the clock’s accuracy did not satisfy the terms set by the Board of Longitude, so Harrison requested (and received) financial support to continue.

Harrison commenced work on his second design (H2) in 1737, but by 1740 he realized a design defect, and so he immediately started work on a third clock. After 15 years of work on it, he realized that it, too, would probably not meet the Board’s requirements, so he requested support once more to build a new design (while continuing for four more years to work vainly on H3). For his fourth design, Harrison abandoned his clock designs completely in favor of a watch design. In the meanwhile, the Royal Society granted Harrison its 1749 Copley Medal.

H4 measured a mere 13 centimeters in diameter, but it outperformed his previous three efforts. His son, William, tested its accuracy on a voyage to the West Indies, departing on the Dep-ford on November 18, 1761, and arriving in Jamaica on January 19, 1762, with H4 only 5.1 seconds behind Greenwich Standard Time. William then embarked on a second trial, to confirm the first, on March 28, 1764, aboard the Tartar. Forty-seven days later, the ship landed at Madeira in Barbados, with H4 only 39.2 seconds behind—three times as accurate as required by the Board of Longitude guidelines.

The Board, however, waffled on awarding the prize. Ostensibly, they believed the watch’s accuracy to be a fluke, but in reality, the Board was trying to save the prize for Nevil Maskelyne, the incoming Astronomer Royal, who was also vying for the money. The Board made outlandish demands, asking to see Harrison’s secret designs, and insisting on retaining all four timepieces (H1 through H4) before granting the first 10,000 pounds prize money; to earn the second half of the prize, Harrison had to provide two more watches capable of equaling H4′s accuracy.

The two duplicates of H4 were constructed by Harrison’s son, William, and by Larcum Kendall, a prominent horologist who probably contributed to the construction of H4. H5 (William’s copy of H4) and K1 (Kendall’s copy) were both completed by 1769 and inspected the next year, but the Board continued to resist, insisting that all copies must be made by the Harrisons. On January 31, 1772, Harrison sent a letter to King George III via Stephen Demain-bray, the king’s private astronomer. The king personally attended a trial that attested to the incredible accuracy of the H4 design, but the Board refused even the king’s appeal.

Finally, an act of Parliament in June 1773 won Harrison another 8,750 pounds (he never received the full amount) and recognition that he had indeed solved the longitude problem. Captain Cook confirmed the clock’s accuracy on a three-year voyage (during which K1 lost less than eight seconds per day), returning in July 1775. A year later, Harrison died on March 24, 1776, at his home in Red Lion Square in London.

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