Compass application of navigation history

The compass was applied to navigation in the Song Dynasty. Ocean routes have not expanded, but navigation technology has made epoch-making innovations. The application of compass in ships is a major breakthrough in navigation technology. The compass was invented by China, and its application in ships began in China. The earliest records are Zhu's "Zhou Pingke Tan" and "Xuanhe's Mission to Korea". The use of compass in navigation not only solves the problem of finding the direction at sea in bad weather, but also opens the way for instrument navigation, so that human beings can really get rid of the shackles of the coast and gallop on a wider ocean. The improvement of navigation technology, in turn, promoted the improvement and development of compass, and created a more suitable magnetic compass, also called magnetic compass (see compass). In the Southern Song Dynasty, Wu's Liang Lumeng said, "When the wind and rain are dark, you should only follow the dial." This is the magnetic compass. After the marine magnetic compass was introduced to Europe through Arabia in the12nd century, European seafarers began to use it. At present, the universal magnetic compass on board is a naval magnetic compass improved by British scientist Kelvin at the end of 19. Shen Kuo, a scientist in the Northern Song Dynasty, discovered the influence of geomagnetism on the compass. He recorded the existence of geomagnetic declination in Meng Qian Bi Tan, a scientific conclusion that the geomagnetic declination is different in different places. This discovery was four centuries earlier than the same discovery of Columbus 1492 crossing the Atlantic Ocean. The magnitude of geomagnetic declination is 1580 W. Ballard, that is,1125' e.1724g Graham proposed that the electromagnetic declination changes year by year according to the observation results. Compass self-discipline was also first put forward by China. 1652 or so, Fang Yizhi's Essentials of Physics mentioned the interference of iron on magnetic needles, and the reason why nails are not suitable for seagoing ships, because "salty seawater also hinders magnetism". In the west, self-deviation was discovered in18th century. 1724 or so, the Englishman J. Smith found that the nails in the wooden box would affect the direction of the needle. 180 1 ~ 1802, the British captain M. flinders found that placing a vertical soft iron in front of the compass can partially correct the deviation of the compass. So now there is a copper vertical tube in front of the magnetic compass, and the cylindrical soft iron is stored in it. From 1839 to 1855, British astronomer G.B. Airy suggested that arranging magnetic rods in front of, behind, left and right, and up and down of the compass can minimize the deviation of the compass. Navigation marks have been established along the ancient Mediterranean coast. In 660 BC, a lighthouse was built in Troy in the northwest of Asia Minor, which may be the ancestor of the lighthouse. Around 280 BC, the lighthouse built in Alexandria, northern Egypt, was more than 200 feet high and was one of the seven wonders of the ancient world. 1732, Britain began to set up a boat at the mouth of the Thames, and hung a lamp on the transverse truss to guide the boat. This is the first light ship. The United States deployed buoys on the Delaware River at 1767 before the War of Independence, and later changed to cylindrical buoys at 1820. In the same year, the first light ship was built in eastern chesapeake bay. 1850, the U.S congress stipulated the color and numbering system of waterway signs. 19 ended, and bells, sirens and light buoys came out one after another. 19 10, a high-voltage calcium carbide gas luminous buoy was installed in Anbu Lu Si waterway in new york, and the effect was very good. In Yuan Dynasty, China transported grain by sea and sailed along the coast. There are many shoals and reefs in the waterway, which often lead to the tragedy of sinking ships. In the senior year (13 1 1), Haidaofu set up a beacon boat at the west shoal mouth of the Yangtze River estuary according to the suggestion of Changshu boatman Su, and set up a flag on the boat to guide grain ships to enter and leave. From the first year to the fourth year of Yanyou (1314 ~1317), flags were set up in Jiangyin Xiagang and Xugou. In front of Longshan Temple, the mound was built very high and surrounded by stones. On the mound, flags are hung high during the day and brightly lit at night to guide the grain ship to sail. The installation of these navigation AIDS has played a beneficial role in ensuring navigation safety, especially coastal navigation safety.