John Harrison Chronometer Age Determination, H1, H2, H3, H4, H5 Grasshopper Escapement
Who was John Harrison?
- Dates of birth and death: 1693 – 1776
- Origin: Yorkshire, England
- Occupation: self-taught carpenter → watchmaker
- Achievement: Developed the first precise marine chronometers to determine longitude at sea .
- Winner (after a long dispute) of the British Board of Longitude Prize .
Its genuine watches and serial numbers
The five famous Harrison watches (H1 – H5)
| Designation | Year of construction | type | Location today |
|---|---|---|---|
| H1 | 1735–1736 | First marine chronometer (huge) | National Maritime Museum Greenwich |
| H2 | 1740–1741 | Improved version | National Maritime Museum Greenwich |
| H3 | 1750–1759 | Experimental,compensation clock | National Maritime Museum Greenwich |
| H4 | 1755–1759 | Pocket watch format chronometer | Science Museum London |
| H5 | circa 1770 | Final version, tested before King George III. | Worshipful Company of Cloc |
John Harrison (* 24 March Jul. / 3 April 1693 Gregor. in Foulby near Wakefield , Yorkshire ; † 24 March 1776 in London ) was an English carpenter , inventor and self-taught clockmaker .
By developing a highly accurate, ship-worthy clock, he solved the so-called longitude problem , for which England had offered a substantial prize in 1714. His clocks enabled, for the first time, precise mechanical time measurements and thus the accurate determination of longitude at sea.
Life
Little is known about John Harrison's early life. He was the eldest of five children. In his youth, he learned the carpentry trade from his father.
At just under 20 years old, Harrison constructed his first pendulum clock in 1713, which can still be seen today in the exhibition rooms of the Worshipful Company of Clockmakers in Guildhall . The reason for building the clock, as well as where he acquired the necessary knowledge, remains unclear. In 1715 and 1717, he built two more very similar pendulum clocks.
In 1718 he married Elizabeth Barrel (1693–1726), with whom he had a son. After his wife's death, Harrison married Elizabeth Scott (c. 1702–1777) in 1726, with whom he had two more children.
Between 1725 and 1727, Harrison and his brother constructed two large grandfather clocks . In doing so, he introduced important innovations such as the grasshopper escapement and the gridiron pendulum . These innovations enabled them to achieve an enormous level of accuracy for the time (approximately one second deviation per month).
From 1727 onwards, John Harrison began to deal with the construction of ship's clocks and the associated problem of length.
His grave is located in St John's Churchyard, Hampstead
Source: Watchwiki, Wikipedia, AI, Google
