Imray Norie's Nautical Tables

Since J W Norie published the first edition of his Complete Set of Nautical Tables and Epitome of Practical Navigation in 1803, many changes to the tables have been necessary in both content and presentation. New tables have been included, obsolete ones deleted to conform with changing techniques of navigation, with the aim of improving the accuracy of the calculated position and reducing the tedium of the calculation. Since the commissioning of the Global Navigation Satellite System (GNSS), its proven accuracy and reliability in all weather conditions have resulted in confidence and almost unquestioning dependence on its ability to provide a vessel's position, course and speed. Its use is widespread but the marine environment is a hostile one and failure of electronic equipment or of the system itself is a possibility. No prudent seafarer would proceed on an ocean passage without a reliable navigational back-up. The Explanation is in the form of a detailed step-by-step description,