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History of hours key dates Time dictionary Interesting facts about the clock     www.clock-history.com     Essays on the history of watch cases   Nautical clock The era of compact and portable mechanical chronometers opened the invention are the same Huygens in 1675 rotary actuator, as well as the use of weights instead of springs. Compound torsion pendulum, a spiral spring and anchor running paved the way not only to marine navigation, but also the creation of massive small hours, but still significantly increased the accuracy of astronomical observations, and even found the uneven rotation of the Earth. Nevertheless, lunar tables, drawn up by astronomers of that time to determine longitude, still «sin» inaccuracies - from 1 to 2,5 °, corresponding to error as much as 60-150 km - in Paris and London, 100-250 km - near the equator. So strongly required improved methods for navigation and, consequently, more accurate marine chronometers. And it was not just wishful thinking Korabelshikov, and most important task of navigation. September 29, 1702 fleet average of 21 ship under the supervision of Admiral Klodisli Shovela came from Gibraltar to England. The weather was not important, but as soon as the sky cleared of clouds, navigator was able to determine the latitude of location. But longitude, at the time could not accurately measure ... The result of errors in the calculations was that 5 ships in the squadron in a fog naleteli Gilstonskie reefs and 1 600 people, including the admiral, hero of the Anglo-French war dead. This tragedy has become for Britain a terrible shock. Soon, the Parliament has prepared a bill, which is unprecedented for the time the huge size of reward in 20 thousand pounds (which was equivalent to 150 kg of gold) due to the person who, in practice, solve the problem of determining longitude at sea. But despite the fact that hronometrichesky method of determining longitude was known, was waiting for his hero award 60 years ... Nautical clocks were manufactured in 1735 Yorkshire carpenter John Harrison. Their accuracy is ± 5 seconds per day, and they were well suited for marine travel. However, remained dissatisfied with his first chronometer, the inventor has worked for almost three decades before in the 1761-m full-scale testing began the improved model, which left less than a second per day. The first part of awards received Harrison in 1764, after three long sea-trials and at least long ordeal office. Fully reward the inventor was only in 1773. Tested chronometer Captain James Cook, that was thanks to his stake Islands Polynesia. In the logbook, he lauded praise brainchild of Harrison: «true friend - the clock, our conductor, who never brings». Since then, the notion of «navigation» and «time» were truly inseparable.