National Maritime Museum, London
Willem van de Velde's painting from around 1700, ''Two English Ships Wrecked in a Storm on a Rocky Coast,'' illustrates the hazards of navigation without reliable positioning techniques.
The Race That Changed the World and Made the Watch
|By Roderick Conway Morris|
London 3 September 2014
The ancient Greeks were the first to use a grid system to map the world, but while latitude — the distance north or south of the equator — was relatively easy to calculate by observation of the sun or stars, the measurement of east-west longitude proved a far more stubborn challenge.
The Renaissance rediscovery of Greek science stimulated generations of mathematicians and scientists to seek a solution, from the Italian Galileo Galilei and the Dutchman Christiaan Huygens to the Englishmen Isaac Newton and Nevil Maskelyne. Ultimately it was a series of determined English clockmakers who solved the problem.
Europe's maritime expansion and the fierce competition between nations to dominate lucrative trade routes made the calculation of longitude an ever more pressing concern. Several countries, including Spain, the Netherlands and France offered rewards, but in 1714 Britain upped the stakes with the passage of the Longitude Act, which provided for "a Publick Reward for such Person or Persons as shall Discover the Longitude at Sea." The prize money made available, £20,000, was enormous — the equivalent of the annual wages of 600 craftsmen.
The original manuscript of the Longitude Act is for the first time on public display in "Ships, Clocks & Stars," an exhibition running through Jan. 4 at the National Maritime Museum in Greenwich, England. Put together by Richard Dunn, the museum's senior curator for the history of science, and the science historian Rebekah Higgitt, it marks the 300th anniversary of the act.
All five of John Harrison's epoch-making marine timekeepers, now referred to as H1 through H5, are on show, as well as those by other key players, notably the clockmakers Larcum Kendall, Thomas Earnshaw and John Arnold & Son. These are accompanied by scores of other astronomical and navigational instruments, contemporary documents, portraits, paintings, engravings and books.
The show opens with a dramatic canvas by Willem van de Velde of around 1700, "Two English Ships Wrecked in a Storm on a Rocky Coast," to illustrate the hazards of navigation without reliable positioning techniques: The curators' catalog notes that one in five ships sailing between Portugal and India between 1550 and 1650 were lost at sea. A disaster off the Scilly Isles in 1707, in which Admiral Cloudesley Shovell, a returning war hero, and 2,000 sailors were drowned, was a stimulant to Parliament to pass the Longitude Act.
The next section focuses on the most promising proposals that were put forward after the act. These included using Galileo's method of observing the orbits of Jupiter's moons; charting patterns in the earth's magnetic field; calculating lunar distance; and regularly firing rockets from stationary ships moored at intervals along sea routes.
All had serious practical drawbacks. Indeed, the promised reward produced a kind of longitude fever that swept Britain and beyond, and gave rise to a host of ever more outlandish proposals.
Many thought the whole enterprise a vain pursuit, and satirists had a field day. The final plate from Hogarth's "Rake's Progress" — the Bedlam scene, set in a madhouse — includes a benighted inmate obsessively sketching longitude projects on the wall. Even the word "chronometer," coined in 1714 as a mock pseudo-technical term in a book, "The Longitudes Examin'd," did not gain serious currency until the 1780s.
In evidence to Parliament before the Act, Isaac Newton had placed at the head of putative solutions "a watch to keep time exactly" but added that one that would keep time at sea "hath not yet been made."
The introduction of pendulum clocks in the 1650s greatly increased accuracy. On show for the first time, from a private collection, is the movement of the metronome-like Oosterwijck Sea Clock, developed in the early 1660s with the collaboration of the Dutch mathematician Christiaan Huygens, almost a century before Harrison's H4 sea watch finally solved the problem in 1759.
Still, no amount of finessing of pendulum clocks could adapt them to perform reliably under rough conditions at sea.
Harrison's clocks were machines of great beauty, but mind-bending complexity. H1 has more than 1,440 parts — or more than 5,400 if each chain segment is counted separately. He spent 19 years developing his H3 alone: Benjamin Franklin was prepared to spend a substantial sum just to view it.
Before granting Harrison his reward for H4, the Longitude Board insisted that he reveal the secrets of its construction, to satisfy themselves that it could be reproduced at a price that would make it available to navigators at large.
Larcum Kendall — less famous than Harrison but a major figure in this exhibition — managed to replicate H4 in the form of what became known as K1, although still at enormous cost. He warned the board that simplifications would have to be made were such chronometers ever to be made widely available. This he triumphantly succeeded in doing in his K2 and K3 models.
The baton was subsequently taken up by John Arnold and his archrival Thomas Earnshaw. One of Earnshaw's breakthroughs was to develop a design based on watchmaking component assembly methods rather than one-off clock-making techniques, initiating a manufacturing process that would endure well into the 20th century. His design, consisting of 128 parts plus a box, became the enduring standard for all marine chronometers.
Arnold & Son and Earnshaw between them supplied more than 2,000 box and pocket chronometers, providing for more than half the Royal Navy's needs into the 1820s.
The presence here of so many of these historic timepieces is artfully used in the final sections of the exhibition to open up global vistas of war and peace, exploration and adventure, in which they played a vital part.
K1, completed in 1769, guided Captain Cook on his second and third voyages to the Pacific. It survived shipwreck off Norfolk Island and took the First Fleet of convict colonists to Australia. K2 was taken toward the North Pole in 1773 and was entrusted to Captain Bligh of the "Bounty" for his mission to Tahiti. When he was cast adrift by the mutineers, the chronometer was used by their leader Fletcher Christian to navigate to Pitcairn. It was bought by an American whaling captain in 1806 and, after further vicissitudes, made it back to Britain in the 1840s.
First published: International New York Times
© Roderick Conway Morris 1975-2016