|
The Longitude rewards refer to the system of inducement prizes offered by the British government for a simple and practical method for the precise determination of a ship's longitude at sea. The rewards, established through an Act of Parliament (the Longitude Act) in 1714, were administered by the Board of Longitude. This was by no means the first reward to be offered to solve this problem. Philip II of Spain offered one in 1567, Philip III in 1598 offered 6,000 ducats and a pension,〔 〕 whilst the States General of the Netherlands offered 10,000 florins shortly after.〔 〕 However, these large sums were never won, though several people were awarded smaller amounts for significant achievements. ==The Longitude Problem== The measurement of longitude was a problem that came into sharp focus as people began making transoceanic voyages. Determining latitude was relatively easy in that it could be found from the altitude of the sun at noon with the aid of a table giving the sun's declination for the day.〔Latitude can also be determined in the Northern Hemisphere from the angle above the horizon of Polaris, the northern pole star. However, since Polaris is not precisely at the pole, it can only estimate the latitude unless the precise time is known or many measurements are made over time. While many measurements can be made on land, this makes it impractical for determining latitude at sea.〕 For longitude, early ocean navigators had to rely on dead reckoning, based on calculations of the vessel's heading and speed for a given time (much of which was based on intuition on the part of the master and/or navigator). This was inaccurate on long voyages out of sight of land, and these voyages sometimes ended in tragedy. An accurate determination of longitude was also necessary to determine the proper "magnetic declination", that is, the difference between indicated magnetic north and true north, which can differ by up to 10 degrees in the important trade latitudes of the Atlantic and Indian Oceans. Finding an adequate solution to determining longitude at sea was therefore of paramount importance. The Longitude Act only addressed the determination of longitude at sea. Determining longitude reasonably accurately on land was, by the 16th century, possible by a well established method using the Galilean moons of Jupiter as an astronimical 'clock'. The moons were easily observable on land, but numerous attempts to reliably observe them from the deck of a ship resulted in failure. For details on other efforts towards determining the longitude, see History of longitude. The need for better navigational accuracy for increasingly longer oceanic voyages had been an issue explored by many European nations for centuries before the passing of the Longitude Act in England in 1714. Monarchies in Portugal, Spain, and the Netherlands offered financial incentives for solutions to the problem of longitude as early as 1598. Addressing the problem of longitude fell, primarily, into three categories: terrestrial, celestial, and mechanical. 〔 This included detailed atlases, lunar charts, and timekeeping mechanisms at sea. It is postulated by scholars that the economic gains and political power to be had in oceanic exploration, and not scientific and technological curiosity, is what resulted in the swift passing of the Longitude Act of 1714 and the largest and most famous reward, the Longitude Prize being offered. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Longitude rewards」の詳細全文を読む スポンサード リンク
|