双语科技百科(物理) 第40期:指南针
The Compass
The compass is considered to be one of the four great inventions of anaent China.
指南针是中国古代“四大发明”之一。Before the compass was invented, people depended upon the position of the sun and stars to tell them the direction when at sea, which only worked when it wasn’t cloudy. The invention of compass solved the problem.
在指南针发明以前，人们在茫茫大海上航行，只能靠太阳和星星的位置辨认方向，如果遇上阴雨天，就会迷失方向。而中国人发明的指南针则帮助人们解决了这个难题。
Over 2,000 years ago, inthe Warring States Period, Chi-nese ancestors invented the earli-est compass-Si Nan, also known as the South Pointer. Si Nan was composed of two parts:a spoon and a tray. The spoon was cut from an intact piece of natural loadstone, with its handle as the South Pole and s round,smooth bottom as the center ofgravity. The tray, on the other hand, was made of bronze, and at the center, there was a round, smooth groove, carvedwith checks and words indicating the 24 directions. When the spoon was put into the groove, it would rotate flexibly. When the spoon stopped, its handle would point to the instrument was the predecessor of the magnetic compass.
早在2000多年前的战国时期，我们祖先就发明了最早的指南针——司南。司南由一把“勺子”和一个“地盘”两部分组成。司南勺由整块磁石制成。它的磁南极那一头琢成长柄，圆圆的底部是它的重心，琢得非常光滑。地盘是个铜质的方盘，中央有个光滑的圆槽，四周刻着格线和表示24个方位的文字。司南勺放迸了地盘就能灵活地转动，在它静止下来的时候，磁石的指极性使长柄总是指向南方。这种仪器就是指南针的前身。However, since was easy for natural loadstone ( magnetic iron oxide) tolose its magnetism, Si Nan could not be widely used. During the Northern Song Dy-nashjt, artificial magnetization was discovered, gMng rise to the Pointing-to-the-South Fish, which was made from a piece of thin iron sheet cut into the shape of a fish, magnetized in a geomagnetic field, and put into water, floating and lying ver, due to its weak magnetic field, Pointing-to-the-South Fish was not of much pradical value. On the basis of the Pointing-to-the-South Fish,people replaced the thin iron sheet with a magnetized steel needle, gMng rise to the earliest artifiaally magnetic compass.
由于天然磁石因打击受热容易失磁，磁性较弱，因而司南不能广泛流传。到宋朝时，有人发现了人造磁铁，进而发明了指南鱼。人们把经过磁化的薄片做成鱼的形状，将其放入水中即能浮在水面并指示正南北方向。后来，人们将指南鱼再加以改进，把带磁的薄片改成带磁的钢针，创造了人造磁体指南针。The compass was soon employed in navigation. The earliest record on using the compass in navigation was in Zhu Yu’s Pin,g Zhou, Ke Tan ( written belween 1119～ 1125 ) ,which recorded Zhu Yu’s experiences in Guangzhou ( South China’s Guangdong Province) , where navigation was highly also wrote a-bout some of the experienced sailors, The sailors know how to pinpoint the ship’s position; they watch the stars a night and the sun in the day, and when is cloudy, they use the might be the earliest record on the use of the compass in the world’s navigational iated by the Chinese people, this newigational instrument was a grand innovation in ncrvigation technology.
指南针发明后很快就应用于航海。世界上最早记载指南针应用于航海导航的文献是北宋宣和年间(1119~1125)朱或所著《萍洲可谈》。该书记录了他在广州时的见闻，还记载了申国海船上很有经验的水手：“舟师识地理，夜则观星，昼则观日，阴晦则观指南针。”这是全世界航海史上使用指南针的最早记载。我国人民首创的这种仪器导航方法，是航海技术的重大革新。Soon after, Arabian sea boats also employed the navigation device, and went on to introduce it to the European countries. As Friedrich Engels, pointed out in his book Natural Dialectics,“The magnetic needle arrived in Europe via the Arabs in around 1180.”The stcrtemenf shows the Europeans applied the compass in ncrviga-tion 80 years after the Chinese.
中国使用指南针导航不久，就被阿拉伯海船采用，并经阿拉伯人把这一伟大发明传到欧洲。恩格斯在《自然辩证法》中指出，“磁针从阿拉伯人传至欧洲人手中在1180年左右”。中国人首先将指南针应用于航海比欧洲人至少早80年。The famous saentist Shen Kuo (the author of Dream Creek Notes ) of the Northern Song Dynasty discovered the existence of magnetic declination( the angu-lar devicrtion of a compass needle from true north) , after performing many saentffic pointed out correctly that the magnetic poles of the earth were not in uniformity with the geographic poles. The use of marine compass and the theory of magnetic declincrtion combined played a most important role in the tong-distance sea voyages. For the first time in history, humans were able to navigate freely un-der any kind of weather e many new sea routes were opened to traffic, promoting the exchange of culture and trade among the people of the s fail to describe the compass importance to navigcrtion.
北宋著名科学家沈括（《梦溪笔谈》著者），在制作和应用指南针的科学实践中发现了磁偏角的存在。他精辟地指出，这是因为地球上的磁极不正好在南北两极的缘故。指南针及磁偏角理论在远洋航行中发挥了巨大的作用，人类第一次得到了在茫茫大海中航行的自由，从此开辟了许多新的航线，促进了各国人民之间的文化交流与贸易往来。指南针对航海事业的重要意义怎么说也不为过。Joseph Needham, a famous historian, once said to Chinese students:“In the realm of navigation, your ancestors were much more advanced than our ances-tors. Far before Europe, the Chinese already harnessed the wind power, with the coordination of fore (front)and aft ( rear) sails to navigate in any direction of the wind they aps for this reason, in the history of navigation, China never used the galleys, which were rowed along by slaves as in anaent Greece or Rome.”
西方著名历史学家李约瑟曾对其中国学生说：“你们的祖先在航海方面远比我们的祖先来得先进。中国远在欧洲之前懂得用前、后帆的系统御风而行，或许就是这个原因，在中国航海史上从未用过多桨奴隶船。”The invention of the compass had epochal influence on navigation, opening up a new chapter in the history of world navigation. With its help, Admiral Zheng He made seven voyages across seas to Southeast Asia and around Indian Ocean in the early Ming Dynasty (1368 ~ 1644) , Christopher Columbus discovered the New Word, and Ferdinand Magellan sailed round the world.
指南针的发明，给航海事业带来了划时代的影响，世界航运史也由此翻开了新的一页。明朝初期郑和率领船队七下西洋，15世纪哥伦布发现新大陆和麦哲伦环绕地球航行等壮举，都是指南针用于航海事业的结果。
