LONGITUDE ACT (1765). An Act for rendering more effectual an Act made in the Twelfth Year of the Reign of Her late Majesty Queen Anne, intituled, An Act for providing a publick Reward for such Person or Persons as shall discover the Longitude at Sea, with regard to the making Experiments of Proposals made for discovering the Longitude.

DISCOVERY OF LONGITUDE AT SEA. Great Britain. Parliament.

Published by London: Mark Baskett and the Assigns of Robert Baskett, 1765

About this Item

Folio (12 inches). 5 George III, Chapter 11. Title leaf + pages 271-274. Woodcut Royal coat of arms and decorative initial. Text in Black Letter. Neatly extracted from a bound volume. 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 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 (1765) reiterated specific goals of the program, and approved an additional GBP 2,000 for continued research work and experimentation. Seller Inventory # 155

Bibliographic Details

Title: LONGITUDE ACT (1765). An Act for rendering ...

Publisher: London: Mark Baskett and the Assigns of Robert Baskett

Publication Date: 1765

Binding: Soft cover

Condition: Very Good

Edition: 1st Edition