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Folio (11.75 inches). 46 George III, Chapter 77. Caption title, pages 709-711. Engraved Royal coat of arms. Neatly extracted from a bound volume and expertly mended. One of the greatest dangers facing early mariners was the inability to determine accurate position at sea. Over the centuries, many lives had been lost at sea, but it was the loss of nearly 2,000 lives in 1707 (when four British navy ships ran aground as a result of miscalculated longitude) that prompted a Parliamentary investigation. The resultant Longitude Act (1714) offered prize money of up to GBP 20,000 (reduced to GBP 10,000 in 1774) for a reliable and accurate method of determining Longitude at Sea. The contest was expanded in 1745 and 1765 to include the search for a North West Passage between the Atlantic and Pacific oceans, also with reward money of up to GBP 20,000. The program was further broadened in 1818 to include navigation to the high Arctic and the North Pole (with prize money of up to GBP 5,000) and relaxed certain regulations to entice northern whale hunters to participate in the contest. Research and related experimentation were also encouraged, and award money was made available for lesser discoveries and specific improvements. The competitions attracted the skill and imagination of the greatest scientific minds and mariners of the time. It was known that the Earth rotated through fifteen degrees of longitude every hour, and if the exact times were known for two locations (the local time, and the time at some geographically known location, such as the Royal Observatory at Greenwich), the time difference would represent the longitudinal separation. For this method, an accurate knowledge of time was essential, and spawned the race to develop a reliable marine chronometer that could maintain accurate time during long and rough voyages. Competing with the Chronometer Method were the mathematicians who promoted the Lunar Distance Method, whereby longitude could be calculated using certain astronomical measurements combined with specific numerical corrections that were made available in yearly Nautical Almanacs. The government-appointed Board of Longitude administered the program, scrutinized submissions, awarded prize money, and oversaw publishing of Nautical Almanacs. Objectives and rules were outlined in some two dozen Parliamentary Acts issued between 1714 and 1828. The Longitude at Sea program was successful in multiple ways, and facilitated important advances in mathematics, astronomy, horology, navigation, and Arctic exploration. Over the life of the program, a total of GBP 53,000 in prize money was awarded to more than sixty participants. The most prominent and successful competitor was John Harrison (1693-1776), who received disbursements of GBP 22,000 over a period of 35 years for his brilliant discoveries and invention of the marine chronometer. The Longitude Act (1806) extended the aims of the Longitude Act (1803) and approved an additional GBP 10,000 for paying current debts, conducting related experiments, and for awards to recognize lesser contributory discoveries as approved by the Commissioners of the Board of Longitude. Seller Inventory # 164
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