The Longtitude Challenge

The Longitude Challenge:

Anyone living in the eighteenth century would have known that ?the longitude problem? was a scientific dilemma and had been for a long time. Without the ability to measure longitude, it was difficult for sailors to navigate. The problem was so immense that prizes were offered for the first person to solve the problem.

There were several competitors to solve ?the longitude problem,? including Galileo, Sir Isaac Newton, Christiaan Huygens, Jean Dominique Cassini, and Edmond Halley. Finally two reasonable methods were presented: the Lunar-Distance method and the Chronometer method. Once and for all John Harrison?s marine chronometer solved ?the longitude problem.?

Galileo first observed the moons in 1610 and 1612. He constructed charts of their movements. His observations were so accurate that he could predict their positions for the next several months. In 1616 Galileo proposed to the Spanish Court a way to measure time. It could be calculated at any point on Earth, using the moons of Jupiter. His proposal was taken a lot more seriously by Holland rather than Spain. Interest was lost in Galileo?s method soon after he died.

In 1714 the matter of finding the longitude at sea, was brought up to the House of Commons by many of the captains of Her Majesty's ships and London merchants. Isaac Newton presented evidence of several projects. One project was a watch that could keep time exactly. Another was similar to Galileo?s studies by using the moons of Jupiter, but to use the eclipses of Jupiter?s satellites, and the last was a new method proposed by William Whiston and Humphrey Ditton. They proposed:

"... A number of lightships be anchored in the principal shipping lanes at regular intervals. The lightships would fire at regular intervals a star shell timed to explode at 6440 feet. Sea captains could easily calculate their distance from the nearest lightship merely by timing the interval between the flash and the report." (1)

Newton disapproved of all of the proposals, to him they were all good ideas but when tested didn?t persist.

In 1666 the French AcadÐ"©mie Royal des Sciences was founded. Its chief minister was Jean Colbert, who invited several scientists to come and work there, including Christian Huygens. Huygens was not from France so he went back home to Holland and often returned to work on longitude. Huygens was recognized when he patented the pendulum clock in 1656. Several of his clocks had been tried at sea but weren?t very successful. Huygens continued to try and perfect the faults of his pendulum clock with sea trials.

Jean Dominique Cassini also was trying to solve ?the longitude problem? at AcadÐ"©mie