Marine geography science is one of the main foundations and prerequisites to promote navigation practice, which in turn becomes the most important condition and motive force for the development of marine geography science, and the two promote each other. Marine geography science also permeates the history of navigation, science and even the whole history of civilization. This year marks the 5 10 anniversary of Columbus's discovery of America. While remembering this great navigator, it is of great significance to study Columbus' navigation function from the perspective of marine geography science, which will expand the boundary of Columbus' navigation research, innovate the research content and highlight the characteristics of the times.
First, marine geography science and the formation of Columbus's thought and action of going to the West.
There are many people who denigrate Columbus's successful voyage. For example, Columbus was a liar, a madman, mentally abnormal and puzzled all his life, and his discovery was accidental success [1]. From the perspective of marine geographical science, these statements are groundless.
1. Before sailing, Columbus had a profound and extensive knowledge of marine geography.
In Columbus' time, Western Europeans didn't know much about the Far East. The description of oriental "gold" in Marco Polo's Travels aroused the growing desire of kings, feudal nobles, monks and businessmen in western Europe. Western Europeans explore with great enthusiasm and cooperate to find new routes. When they went to Columbus, the Portuguese had been exploring south along the west coast of Africa for decades and had made achievements. The works of Kyle Poirot deeply attracted Columbus. He read them carefully, not only intensively, but also did research. Located in the Columbus Memorial Hall in Seville, Spain, there is still a Latin book "Marco Polo's Travels" with Columbus's eyebrows in it. A rich and distant east attracted him deeply.
Since 14 entered the ship, Columbus first worked as a young trainee sailor in Bordeaux, then in Corsica, and later became a regular sailor. The Mediterranean and the North Atlantic are his maritime homes. 1476, Columbus was killed in a merchant naval battle and drifted to Portugal. At that time, the Portuguese were exploring south along the coast of Africa with great interest, aiming to find a route to the east around the Cape of Good Hope at the southern tip of Africa. They have discovered some islands along the coast of Africa and the Atlantic Ocean, and also explored and sailed to the north. Columbus enlisted in Portugal and made his first voyage to Bristol, Galveston and Iceland. During his voyage in Portugal, Columbus further studied and mastered astronomy, geography, tides, wind direction and other knowledge, especially the knowledge related to navigation. He is familiar with and can operate many types of ships, understand and use the navigation instruments at that time, master the navigation technology, and study and draw charts. He enthusiastically studied and collected all kinds of navigation materials, learned to use Italian, Spanish, Portuguese and Latin, and became a navigation expert. As he himself said in 150 1, "I have been in the ocean since I was a child, and I have been insisting on sailing at sea until now. Navigation technology inspires those who are loyal to navigation to explore the secrets of this world. After fully studying astronomy and geometric arithmetic, I can concentrate on drawing the shape of the earth and the cities on it easily. " Through continuous study and practice, Columbus formed the idea of sailing to the west. 2. Firmly believe in the theory that "the earth is round" and that sailing to the west can lead to the east.
Science is developing constantly, and its correctness and its role in social practice have its epochal and relativity. In Columbus' time, many contents of marine geography were wrong today, but they were advanced at that time, which also guided people's practice and played their due role. The theory that the earth is round has been recognized and become an orthodox view, which is a modern thing. Before that, in ancient and medieval times, people had various views on the shape of the earth where they lived. Pythagoras in the 6th century BC and Plato later may be the first philosophers to put forward the concept that the earth is a sphere. They claim that the earth is the center of the universe and celestial bodies move around it in circles. On the basis of advocating the theory that "the earth is spherical", Poseidon, a famous scholar, speculated that sailing from the Mediterranean to the west could reach India. In the 2nd century AD, Ptolemy, a famous geographer, wrote the masterpiece of classical astronomy "Grand Synthesis". He believed that the earth was a central sphere around which celestial bodies revolved. Ptolemy's Guide to the Earth, with eight volumes, is a comprehensive geographical work with far-reaching influence. The book divides the earth into 360 degrees by latitude and longitude net, and discusses the circumference, various place names, land, ocean, shape and temperature difference of the earth [2] (pp.142-148) [3] (pp.175-1. Of course, due to the limitations of the times, the mistakes in this book are quite big, but it is the crystallization of geography in that era.
With the development of society, the academic works of ancient Greece and the academic thoughts of Muslims in the Middle Ages were absorbed by Western Europe and translated into Latin after 12 century. The upsurge of collecting and translating ancient Greek culture in western Europe is due to the increasing demand for new knowledge. By the time of Columbus, the works of ancient Greek and Muslim writers had been translated into Latin in a large number and variety. Columbus used his Latin to read a lot of ancient Greek works, especially Ptolemaic astronomy and geography. He also studied the relevant works of medieval scholars and gradually came into contact with the "Earth Circle Theory".
In Kyle Polo's travels, it is said that Shibangge (Japan) is not far from the Indian coast. In addition, Pierre, a French geographer a little earlier than Columbus? Daley's book Imagine Muudi had a great influence on Columbus. This book is based on Aristotle and the medieval thinker Roger? Bacon's point of view, Aristotle thinks that the ratio of water to land on the earth's surface is 1:6. The book describes Europe and Asia as "long" lands extending to both sides, while the sea between the two continents (referring to the waters west of Europe and east of Asia) becomes narrow and "short". The book also points out that "the end of Iberian Peninsula and the eastern end of India are not too far from each other ... obviously, it can be reached in a few days with the wind" and asserts that "the ocean extending between Spain and India is not very wide." [4] (pages 76-77) In addition, according to the Christian Old Testament, "On the third day, you should collect water in the seventh part of the earth and dry up the other six parts." The academic views of ancient Greece are consistent with religious documents, which played a special role in Columbus' pursuit of academic knowledge and religious belief.
Columbus also collected a lot of evidence from all over the world that was ignored by other crew members and could prove that there was a piece of land in the distant part of the Atlantic Ocean. For example, if the west wind continues to blow fiercely, the bodies of Europeans and Africans will not drift into the sea. In addition, he heard from other crew members that a wooden product was caught 450 nautical miles off the coast of Portugal. Obviously, it is not made of metal tools, but it is small and exquisite. Strange tree trunks and other things unknown to western Europeans often rush into the vicinity of the Azores. Through theoretical research and practical observation, Columbus became more convinced of the theory of "Earth Circle".
3. Comprehensive calculation and the final formation of western airline ideas.
According to the achievements of ancient Greek geography, referring to the records of Japan and China in Kyle Polo's book, and the works of Western European scholars in the Middle Ages, Columbus's thought of westward voyage is becoming more and more mature. As early as the end of 1970s in 15, Columbus wrote a letter to the Italian scholar Tuscany, in which he advocated sailing to India from the west road. Tolstoy has many original views on geography, especially the theory of "Earth Circle", which explains the circumference, latitude and longitude of the earth and the distance between Western Europe and the East. He believes that, measured from Lisbon to the east on land, the known continent includes the whole earth surface with 230 longitudes, and it only takes 130 longitudes to reach the east side of the continent from Spain to the west (people didn't know there was the Pacific Ocean at that time). After studying Kelpolo's books, Tuscany thought that sailing 5000 nautical miles west from Lisbon could reach the Great Khan State (China). Another sea route encircles Antila Island. After 2000 nautical miles, you will meet the wonderful Kifeng (Japan). He also drew a map of the North Atlantic. Columbus made a special trip to Tuscany to ask him for advice and obtain relevant information. Many of Tuscany's conclusions are different from those of Aristotle, the Old Testament and The Appearance of the World. As the world has asserted, China lies more than 3000 miles west of the Canary Islands [4](pp76-77). Although Columbus agreed with many viewpoints of Tuscany, he had different views on Tito's route, thinking that it was too long and needed to be calculated by himself.
In order to practice sailing, Columbus also faced two problems, both of which were related to the distance from sailing westward to Asia. One is, if the earth is 360 degrees, how long is 1 degree? 2. How long does the known land on the earth extend eastward? According to the Old Testament and Aristotle's statement that land accounts for 6/7, the ocean between Europe and Asia only accounts for 360 degrees 1/7, that is, 5 1 longitude. Considering the world and Kyle Polo's travels, the result of Columbus calculation is that the land area accounts for 290 degrees from east to west. So his answer is that the oceans on the earth account for 70 degrees. But how long is 1 degree? According to Ptolemy's calculation in ancient Greece, and several measuring methods such as medieval Muslim scholars measuring two points on the same meridian, 1 degree is 62.5 nautical miles. There are also some geographical works that say that the length of 1 degree is less than 10 nautical mile. Columbus accepted the smaller numbers in the world.
Since the earth is round and the distance between the two longitudes at different latitudes is different, what is the distance between the two longitudes at the latitudes of Lisbon or Azores? According to the data knowledge at that time and the calculation method of researchers of Portuguese navigation institutions, Columbus calculated that 1 degree was equal to 50 nautical miles. According to this standard, it is less than 3550 nautical miles from the target in the east (in fact, the distance from the Canary Islands to Japan is 10600 nautical miles along the 28-degree latitude), so it can be seen that Columbus's calculation result is wrong due to the limitation of conditions. According to this result, it is much easier to cross the Atlantic eastward [5].
However, it was this "mistake" that finally strengthened Columbus' confidence. This theory, together with the enthusiasm and adventurous spirit of searching for gold, charting sea routes and spreading Christianity, prompted Columbus to implement the westward voyage plan. After many unsuccessful applications to the Portuguese king, he came to Spain again. After many hardships, he broke through many obstacles and finally promoted the action.
Columbus's voyage to the West and his discovery of America were not "irrational behavior" or "accidental success", let alone influenced by "golden dream" and "religious fanaticism". He is a great navigator with a scientific mind, unique insights and pragmatic attention.
Second, discover the contribution of the United States to marine geography.
Columbus made great contributions to marine geography in his navigation activities. He was the first to enter the "American Mediterranean" and discovered almost all the Bahamas and Antilles, covering dozens of American countries and regions. He made a survey of marine geography and hydrology and made many discoveries. Here are only the following aspects.
1. laid the foundation for the development of global routes and the final confirmation of the "Earth Circle Theory".
The scientific culture of ancient Greece was severely damaged in the late ancient times and early medieval times in western Europe. In the middle ages, the concept of the earth was a map composed of fantasy according to the interpretation in the Bible. People think that the earth is a disk floating on the water, the sky is a vault supported by four pillars, and the Christian holy land Jerusalem is located in the center of the earth, with land in the middle and water around it, and there are three continents: Asia, Africa and Europe. In Christian Western Europe before and during the Middle Ages, this view was dominant. 12 and 13 centuries later, the "Earth Circle Theory" began to rise in Europe. Columbus came into contact with the "Earth Circle Theory" from The Travels of Marco Polo, learned about the East, and combined with his own navigation practice and experience to strengthen this concept. Although Columbus was a devout Christian, he deviated from the Christian theory about the shape of the earth. Because he believed in "the theory of the circle of the earth", he made a careful calculation according to all kinds of relevant geographical scientific knowledge that he could come into contact with at that time, and obtained the approximate circumference of the earth and the distance from Western Europe to the East, which provided a scientific theoretical basis for his navigation. Although his calculation results are quite different from the reality, this "wrong" theory is one of the most important factors that led him to discover America. It should be pointed out that advocating sailing from western Europe to Asia is not only to fight against the dangers of nature, but more importantly, to fight against social and man-made difficulties and overcome various ideological and ideological obstacles. At that time, most people didn't believe in the theory of the earth circle, and they didn't believe that sailing west could reach the east. At that time, although several countries were exploring, many navigators were not afraid of storms or pirates, but they were afraid to sail into "hell". It is said that the entrance to "Hell" is somewhere in the Atlantic Ocean. On Columbus's first voyage, some people regarded this legend as the most terrible danger. However, Columbus broke through this obstacle with his bold ideas, scientific plans and fearless spirit, and westbound airlines succeeded. Although he didn't find the real East, he discovered America. Through this discovery, he paved the way for his successor to sail around the world successfully. One of the reasons for Magellan's success is based on Columbus's navigation and his practice. Magellan's successful voyage around the world occupies a very important position in the history of marine geographical science and has far-reaching significance. Therefore, Columbus's navigation activities not only opened up a route to America, but also confirmed the theory that the earth is round, which created conditions for opening up a global route in the future. He opened a new era of navigation activities, which has a wide range of social significance.
2. Investigation, discovery and utilization of marine geography.
During the voyage, Columbus always carefully observed and surveyed the hydrology, geography, meteorology and other conditions of the passing ocean, calculated the voyage, distinguished the azimuth and latitude and longitude, carefully drew maps and recorded the log book in detail. His log book is rich in content and is called "one of the most touching documents in the era of geographical discovery", which provides valuable raw materials for future generations to study marine geography and the history of marine science and technology in the West Indies, the Atlantic Ocean and Central and South America [6]([p. 18]). His exploration, observation, discovery and application of marine geography involve many aspects. For example, the mysterious the sargasso sea in the Atlantic Ocean between 20 and 30 north latitude and 40 and 75 west longitude is a wonder of marine geography, and some natural conditions are still difficult to explain. According to archaeological discoveries, ancient Phoenicians have arrived in the sargasso sea. But in the Middle Ages, science was deeply imprisoned in theology, but the sargasso sea was regarded as a god living in the deep sea, who could change his shape at will or even disappear suddenly, so people were afraid of it and never knew it existed. When Columbus sailed through the sargasso sea for the first time, he almost stopped there. He was the first person to record the sargasso sea in detail, and people began to make a real scientific investigation of the sargasso sea.
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Columbus also contributed to the discovery and utilization of the Atlantic wind direction and ocean currents. All these are reflected in the process of sailing with his rich knowledge, experience, brave spirit and smart and decisive talent. For example, after returning from the first voyage, in order to avoid hitting the rocks, I avoided the northeast trade wind belt and sailed at sea for 48 days. On the second voyage, I went north against the trade wind for 93 days. After two voyages, I knew there were trade winds and westerly winds. He was the first explorer to discover and use the Atlantic stroke system. At the same time, he also realized the role of ocean currents. Long ago, he heard and saw tropical fruits, strange sculptures, wood and human bodies from different places on the sea in western Europe. On his voyage to the United States, he saw with his own eyes the ocean current that was later confirmed as the North Equatorial Ocean Current. At the same time, Columbus also found that due to the backward navigation instruments at that time, the geomagnetic deviation (magnetic declination angle and magnetic inclination angle) was different. These discoveries are mankind's first understanding of the ocean, and they are quickly used by later generations.