Commentary: The story of longitude has some real latitude
Have you ever heard of John Harrison? Harrison saw a problem and had a driving vision on how to correct it.
In the late 1600s, more than 200 years after Columbus reached the New World, there were many dangerous problems for men at sea, but one of main concerns was that it was easy to get lost.
Sailors explored along coastlines in order to see where they were, but fog or storms made them lose their bearings.
That is why mapmaking was such an important art in this age. Sea monsters and assorted dangers were drawn at the boundaries of many of early maps to express the dangers that existed beyond borders of a map.
Technology was beginning to assist sailors in calculating where they were, however. Quadrants, for example, were used in the Northern Hemisphere where sailors could sight the North Star and measure its height above the horizon to calculate their location longitudinally.
As sailors neared the equator, however, they needed a new tool. The astrolabe, which reckoned latitude by the height of the sun, became a useful tool in the Southern Hemisphere.
The Portuguese began to create standardized tables that made working out your position on the ocean even more accurate. Compasses were also used, but early sailors did not have the comforting luxury of really being able to know where they were.
Longitude would continue to be difficult to accurately calculate and was a great technological challenge. Such an important problem caused Britain’s Parliament to form the Board of Longitude in1714. They promised to give a substantial prize was promised to the person who could solve this problem.
Harrison was a meticulous London-based carpenter and clockmaker, and had the courage to formulate his own ideas.
He concluded that the solution to measuring longitude lay in accurately comparing the time aboard ship to a home port (eventually Greenwich, England, which has been designated as the Prime Meridan or 0 degrees longitude) using clocks. Two clock times, one in London and one on a ship, could then be used to calculate a geographical distance. In this manner longitude could be determined. One hour of difference between ship time and port time equals 15 degrees of longitude.
Harrison worked for over 40 years on his ideas. He continued to perfect the invention that would finally solve the longitude question. He persisted with courage and great sacrifice. He continued to think creatively and outside the box.
Scholars scoffed at him and his ideas, but he overcame their objections and eventually created the wonderful chronometer, an invention that would save the lives of seamen and allowed them to fearlessly sail the globe.
His invention was finally accepted in 1770s, almost 300 years after the voyages of Columbus. It has even been suggested that his chronometer resulted in Britain’s growth as a naval power.
Read about this achievement in the book, “Longitude: The True Story of a Lone Genius” by Dava Sobel.
American Studies Professor SHERRY NORD MARRON lives in Newport Beach.