Ships, Clocks & Stars – The Quest for Longitude
By Caryn B. Davis
The quest for longitude has eluded mariners, astronomers, and scientists for hundreds of years. Even with the cleverest and most creative minds of the day dedicating their life’s work to its pursuit, it literally took centuries and the loss of countless lives before a viable solution was found that could accurately determine a ship’s position at sea.
“One way of plotting your position on earth is to imagine a grid spread over its surface. Sailors can navigate according to this grid with the horizontal lines giving north-south position or latitude, and the vertical ones east-west position, or longitude. Latitude is easily measured from the angle of the sun or pole star above the horizon, but measuring longitude at sea is much more difficult,” says Elysa Engelman, Director of Exhibits for Mystic Seaport: The Museum of America and the Sea.
The early Polynesians were great navigators and could successfully traverse across thousands of miles of open ocean in outrigger canoes. They memorized the location of over 150 stars, weather patterns, the nuances of the seasons, and the size, speed, and the direction of waves. From this, they knew how to plot a clear course. They were also keenly attuned to their natural environment and by observing where different species of wildlife would congregate at certain times of the year, they could further ascertain their whereabouts. All of this navigational knowledge was kept alive through oral traditions that were passed on to the next generation.
When Captain James Cook, a British explorer and cartographer for the Royal Navy left Tahiti in 1768, he took with him onboard his ship Endeavour, a Tahitian navigator in hopes of learning their techniques. Cook, however, was unsuccessful when he tried to replicate these methods later.
It was not only Cook’s desire as a seafaring man, but also his duty to try and find a solution to the longitude problem as mandated by parliament in 1714 when the Longitude Act was passed. A Board of Longitude comprised of scientists and admirals was established and the offering of a monetary reward to anyone who could resolve the issue expeditiously. The Act was instituted on the heels of one of the worst maritime catastrophes in history known as the Sicily Naval Disaster, when the Royal Fleet collided into rocks during a storm, losing four warships and approximately 1,500 sailors. The fleet had been blown off course due to the severe conditions and the inability to correctly calculate longitude.
Like Cook, many had gone before him in an earnest effort to find a practical and lasting solution. One of the earliest attempts was by Greek astronomer and mathematician Hipparchus, the founder of trigonometry. In the 2nd century BC he “proposed a system of determining longitude by comparing the local time of a place with an absolute time,” thus introducing the idea of how vital it was to find a precise means and way for measuring time onboard a ship.
Various options were explored such as celestial navigation, dead reckoning, judging lunar distance, observing magnetic deviations, and examining the time of occultations or appulses of a star by the moon. The world’s most brilliant minds such as Galileo, Edmund Halley, Tobias Mayer, Sir Isaac Newton, Royal Nevil Maskelyne, Captain William Bligh, John Harrison, and many others worked diligently on this ambition. Out of these experiments came an array of inventions such as sextants, telescopes, celatones, chronometers, octants, compasses, sea clocks, and astronomical tables. Although none of these processes or instruments was completely successful on their own, they were not without merit. They were all stepping-stones leading to the ultimate solution.
Nowadays, mariners have access to HYPERLINK “https://en.wikipedia.org/wiki/Radar”radar, the Global Positioning System (GPS), and satellite navigation systems; whereas prior, they relied on LORAN, a radio based system, and before that, radiotelegraph sets. But even with these modern technologies, the marine chronometer and sextant are still relied upon for backup and carried onboard most ships.
Mystic Seaport: The Museum of America and the Sea located in Mystic, Connecticut, has just launched a new exhibition entitled, “Ships, Clocks and Stars: the Quest for Longitude,” which tells this compelling story. The award-winning exhibit is sponsored by United Technologies Corporation and produced in conjunction with the National Maritime Museum in London, England, which is home to the largest maritime collection in the world.
While Dava Sobel, author of the bestselling book ,“Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time,” makes an excellent case in Harrison’s favor as the person responsible for solving the longitude dilemma, this exhibition seeks to paint a fuller picture.
“This is a story of people building on each other’s work to finally get solutions. The same is true with Harrison. There were generations of clockmakers trying to get timekeepers to work on a ship. But Harrison did come along with some radical ideas of how to make a clock free from the effects of changes in temperature and how to work without oil. When it’s too hot, the oil causes the clock to seize up by making it gritty and slippery. “When it gets too cold, it makes it sticky,” says Richard Dunn, Senior Curator for the History of Science, Royal Museums Greenwich, London, England.
“Crucially, it was Astronomer Royal Nevil Maskelyne’s observations and work on the Nautical Almanac at the Royal Observatory in Greenwich that demonstrated the complementary nature of astronomical and timekeeper methods. Combined, the two methods led to the successful determination of longitude at sea and changed our understanding of the world,” adds Dan McFadden, Director of Communications for Mystic Seaport.
On display are examples of early 18th century sea clocks that predate Harrison’s invention, along with faithful copies of Harrison’s H1, H2, H3, and H4 marine sea-watch, which is considered to be his greatest masterpiece. Three working replicas of these very large, beautiful, and intricate timekeepers provide the centerpiece for the exhibit.
Other objects of interest include the original 1714 Longitude Act; Astronomical tables developed by Nevil Maskelyne, early sextants, octants, and other pertinent instruments; paintings from Captain Cook’s pacific voyages; detailed models of Cook’s and Bligh’s ships; digital displays that bring key longitude concepts and materials to light; and rare items from Captain William Bligh’s journey after he was banished from his ship, The Bounty, during the most famous mutiny in history.
“There is also a local link to this story. During the mutiny, the mutineers wouldn’t let Bligh have the timekeeper K2 that had been issued to him in 1787 by the Board of Longitude for his voyage to the Pacific. The mutineers took it with them when they resettled on Pitcairn Island,” says Dunn. “It was a whaler from Nantucket named Mayhew Folger who rediscovered Pitcairn and was given the sea watch by John Adams, the last surviving member of the mutiny. Folger lost it in South America, but eventually it found its way back to Britain.”
Mystic Seaport was specifically chosen to host this exhibition in partnership with the Royal Museums Greenwich because of their common interests and commitment to preserving maritime history.
“We did an exhibition in 2014 on the longitude story to commemorate the 300th anniversary of the first British Longitude Act,” says Dunn. “We had the means to do an international tour, and Mystic Seaport was an obvious choice and an important maritime museum that could situate that story well with their own organization. And of course, it’s a wonderful location.”
The exhibition is on display now through March 28, 2016. For more information, log onto mysticseaport.org.