1693-1776 astronomicalclock astronomicalclocks biografi biographie biography chronometer chronometers chronomètre clockandwatchmakers clocksandwatchmakers geografischelengte geografischelänge geography gmt greatbritain harrison harrisontimekeepers histoire history historyroyalsociety(greatbritain) horlogemakers horology john kendalltimekeepers largetypebooks literatureinitalian longitude longnowmanualforcivilization lunardistancemethod lunartables measurement messung naturwissenschaften navigasjon navigatie nonfiction research royalsociety(greatbritain) royalsocietyoflondon scheepvaart schiffschronometer science sterrenkunde