Longitude

Part of the solution for the loss of ships to miscalculated longitude called for developing a more accurate instrument for measuring altitudes. Out of this came the sextant, developed independently in 1730 by English mathematician Joseph Hadley and by American inventor Thomas Godfrey. In 1735 English watchmaker John Harrison completed the solution when he developed the chronometer, the first reasonably accurate portable timepiece. With a quality chronometer and a good sighting instrument on board, navigators had a much better chance to find their way. In the 19th century, European academics improved the mathematical methods of making calculations in celestial navigation. In 1884 European countries agreed to make the meridian of longitude that ran through Greenwich, England, the prime meridian. Until this time, each of the major European countries had claimed that the 0° meridian ran through their own capital city. Extracted from mix sources