雙語科技百科(物理) 第40期:指南針
The Compass
The compass is considered to be one of the four great inventions of anaent China.
指南針是中國古代“四大發明”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.
在指南針發明以前，人們在茫茫大海上航行，只能靠太陽和星星的位置辨認方向，如果遇上陰雨天，就會迷失方向。而中國人發明的指南針則幫助人們解決了這個難題。
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多年前的戰國時期，我們祖先就發明了最早的指南針——司南。司南由一把“勺子”和一個“地盤”兩部分組成。司南勺由整塊磁石製成。它的磁南極那一頭琢成長柄，圓圓的底部是它的重心，琢得非常光滑。地盤是個銅質的方盤，中央有個光滑的圓槽，四周刻着格線和表示24個方位的文字。司南勺放迸了地盤就能靈活地轉動，在它靜止下來的時候，磁石的指極性使長柄總是指向南方。這種儀器就是指南針的前身。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.
由於天然磁石因打擊受熱容易失磁，磁性較弱，因而司南不能廣泛流傳。到宋朝時，有人發現了人造磁鐵，進而發明了指南魚。人們把經過磁化的薄片做成魚的形狀，將其放入水中即能浮在水面並指示正南北方向。後來，人們將指南魚再加以改進，把帶磁的薄片改成帶磁的鋼針，創造了人造磁體指南針。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.
指南針發明後很快就應用於航海。世界上最早記載指南針應用於航海導航的文獻是北宋宣和年間(1119~1125)朱或所著《萍洲可談》。該書記錄了他在廣州時的見聞，還記載了申國海船上很有經驗的水手：“舟師識地理，夜則觀星，晝則觀日，陰晦則觀指南針。”這是全世界航海史上使用指南針的最早記載。我國人民首創的這種儀器導航方法，是航海技術的重大革新。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.
中國使用指南針導航不久，就被阿拉伯海船採用，並經阿拉伯人把這一偉大發明傳到歐洲。恩格斯在《自然辯證法》中指出，“磁針從阿拉伯人傳至歐洲人手中在1180年左右”。中國人首先將指南針應用於航海比歐洲人至少早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.
北宋著名科學家沈括（《夢溪筆談》著者），在製作和應用指南針的科學實踐中發現了磁偏角的存在。他精闢地指出，這是因爲地球上的磁極不正好在南北兩極的緣故。指南針及磁偏角理論在遠洋航行中發揮了巨大的作用，人類第一次得到了在茫茫大海中航行的自由，從此開闢了許多新的航線，促進了各國人民之間的文化交流與貿易往來。指南針對航海事業的重要意義怎麼說也不爲過。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.”
西方著名歷史學家李約瑟曾對其中國學生說：“你們的祖先在航海方面遠比我們的祖先來得先進。中國遠在歐洲之前懂得用前、後帆的系統御風而行，或許就是這個原因，在中國航海史上從未用過多槳奴隸船。”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.
指南針的發明，給航海事業帶來了劃時代的影響，世界航運史也由此翻開了新的一頁。明朝初期鄭和率領船隊七下西洋，15世紀哥倫布發現新大陸和麥哲倫環繞地球航行等壯舉，都是指南針用於航海事業的結果。
