Full Description
This book describes the worldwide evolution of land-based visual time signals that were used by mariners in the nineteenth and twentieth centuries for accurate navigation at sea. They followed development of chronometers which were carried in ships to show mean time at Greenwich, the chosen prime meridian. Greenwich time could be compared with local astronomical time to determine longitude, but chronometers were mechanical devices that had to be checked for accuracy. Land-based signals that were regulated by astronomical observations evolved from the ideas in 1818 of Robert Wauchope, a British naval officer who served at the Cape of Good Hope. He inspired introduction of time balls, specifically the time ball at Greenwich in 1833 which set the standard for subsequent installations and is still in operation today. The main emphasis is on the external appearance of time signals at different locations around the world and how they were used by mariners for rating chronometers. Time balls and guns also became popular signals for public use and workplace control but then had social and political implications.
Contents
Part I: Development of Visual Time Signals.- Chapter 1: Foundations.- Chapter 2: Determination of Longitude and Chronometer Rating.- Chapter 3: Ideas for Visual Time Signals.- Chapter 4: The Greenwich Time Ball and its Evolution.- Chapter 5: Time Ball Supply by Maudslay, Sons & Field after 1852.- Chapter 6: Admiralty Lists of Visual Time Signals after 1880.- Chapter 7: British and Irish Time Signals for General Use.- Part II: Visual Time Signals for Mariners around the World.- Chapter 8: Introduction to Part II.- Chapter 9: Worldwide Evolution of Visual Time Signals after 1880.- Chapter 10: British Isles.- Chapter 11: France, Spain, Portugal and Gibraltar.- Chapter 12: Germany and Danzig.- Chapter 13: The Netherlands, Belgium and Scandinavia.- Chapter 14: Russia, Finland and Latvia.- Chapter 15: The Mediterranean.- Chapter 16: South Africa.- Chapter 17: West and East Africa, and Yemen.- Chapter 18: Mauritius.- Chapter 19: Indian Subcontinent.- Chapter 20: Southeast Asia.- Chapter 21: China, Japan and Korea.- Chapter 22: Australia.- Chapter 23: New Zealand.- Chapter 24: Canada, Newfoundland and Bermuda.- Chapter 25: The United States of America, including Hawaii.- Chapter 26: Central America, The West Indies and South America.- Chapter 27: Atlantic Islands.- Chapter 28: Concluding Remarks.
