Before the invention of the compass, human beings often lost their way in the vast sea, resulting in unimaginable consequences. It was the China people who invented the compass that gave human navigation a direction. Compass is a simple instrument used to judge the orientation. One of four great inventions of ancient china. The main component is a magnetic needle which can rotate freely on the shaft. The magnetic needle can be kept in the tangential direction of magnetic meridian under the action of geomagnetic field. The north pole of the magnetic needle points to the geographical south pole, and this property can be used to distinguish the direction. It is often used in navigation, geodesy, travel and military affairs.
the invention of the compass is the result of our working people's understanding of the magnetism of objects in long-term practice. Due to productive labor, people came into contact with magnetite and began to understand its magnetic properties. People first discovered the nature of magnets attracting iron. Later, the directivity of magnets was discovered. After many experiments and studies, a practical compass was finally invented.
Discovery of magnetic phenomena
Our ancestors have accumulated a lot of knowledge in this field in the pre-Qin period, and they often encounter magnetite (mainly composed of ferroferric oxide) when exploring iron ore. These findings have long been recorded. These discoveries were first recorded in several articles in Guanzi: "There is a magnet on the mountain, and there is gold and copper under it." There are similar records in other ancient books, such as Shan Hai Jing. The iron-absorbing characteristics of magnets have long been discovered, and the nine-volume master article of Lu's Spring and Autumn Annals has: "Kindly attract iron, or attract it." At that time, people called "magnetism" "kindness". They regarded magnets attracting iron as the attraction of loving mothers to their children. And think: "Stone is the mother of iron, but there are two kinds of stone: kindness and unkindness. Kindness can attract his children, but unkindness can't."
before the Han dynasty, people wrote a magnet as a "kind stone", which means loving a stone.
since magnets can attract iron, can they attract other metals? Our ancestors made many attempts and found that magnets could not attract not only gold, silver, copper and other metals, but also bricks and tiles. In the Western Han Dynasty, people realized that magnets can only attract iron, but not other objects.
when two magnets are put together and close to each other, sometimes they attract each other and sometimes they repel each other. Now people all know that a magnet has two poles, one is called N pole and the other is called S pole. Like poles repel each other and opposite poles attract each other. At that time, people didn't know this truth, but they could still perceive this phenomenon.
In the Western Han Dynasty, there was an alchemist named Luan Da. He used this property of a magnet to make something like two chess pieces. By adjusting the mutual position of the polarities of the two chess pieces, sometimes the two chess pieces attracted each other and sometimes they repelled each other. Luan Da called it "chess fighting". He dedicated this novel to Emperor Wu of the Han Dynasty and demonstrated it on the spot. Emperor Wu of the Han Dynasty was amazed and delighted. He was named "General Five Benefits". Luan Dali used the properties of magnets to make novel things to deceive Emperor Wu of the Han Dynasty.
The earth is also a big magnet, and its two poles are close to the geographical south pole and the geographical north pole respectively. Therefore, when the magnets on the earth's surface can rotate freely, they will indicate the north and south because of the nature that the magnets repel each other with the same polarity and attract each other with the opposite polarity. The ancients didn't understand this truth, but they knew this kind of phenomenon very well.
the ancestor of the compass-Sina
The ancestor of the compass appeared in the Warring States Period. It is made of natural magnets. It looks like a spoon with a round bottom, which can be placed on a smooth "site" and kept in balance, and can rotate freely. When it is at rest, the handle of the spoon will point to the south. The ancients called it "Sina", and in the book "Han Feizi" at that time, there was: "Wang Li Sina took the time first." "End up in the morning and evening" means to be square and orient. The application of Sina is recorded in Guiguzi, and Zheng people took Sina with them when they picked jade to ensure that they didn't get lost.
In the Spring and Autumn Period, people have been able to grind nephrite and jadeite with hardness of 5-7 degrees into various shapes, so they can also make natural magnets with hardness of only 5.5-6.5 degrees into Sina. In the Eastern Han Dynasty, Wang Chong made a clear record of the shape and usage of Sina in his book Lun Heng. SiNa is made of a whole piece of natural magnet after pondering, and the handle of the spoon is extremely guided, so that the center of gravity of the whole spoon falls right in the middle of the bottom of the spoon, and the spoon is placed in a smooth site, which is surrounded by a four-dimensional stem and branches, and synthesized in 24 directions. This design was completed after long-term research after the ancients carefully observed many phenomena related to magnetism in nature and accumulated a lot of knowledge and experience. The appearance of Sina is the practical application of people's understanding of the polarity of magnet fingers. However, Sina also has many defects. Natural magnets are not easy to find, and it is easy to lose magnetism due to shock and heat during processing. Therefore, Sina's magnetism is relatively weak, and its contact with the site should be very smooth, otherwise it will be difficult to rotate because of the excessive friction resistance, and the expected guiding effect cannot be achieved. Moreover, Sina has a certain volume and weight, which is inconvenient to carry, which may be the main reason why Sina has not been widely used for a long time.
Sina consists of a bronze disk and a magnetic spoon made of natural magnets. The bronze disk is engraved with 24 directions, and the magnetic spoon is placed on the central circular surface of the disk. When it is at rest, the tail of the spoon points to the south.
the invention of the compass
in ancient times, thin iron leaves were often cut into fish shapes, and the belly of the fish was slightly concave, like a boat. After magnetization, it floated on the water surface, which could refer to the north and south. It was used as a game at that time. Cui Bao of the Eastern Jin Dynasty once mentioned this kind of "guide fish" in Notes on Ancient and Modern Times.
in the northern song dynasty, Ceng Gongliang wrote a method of making and using the compass fish in the Wu Jing zong Yao: "Cut it with thin iron leaves, which are two inches long and five minutes wide, and the head and tail are as sharp as fish. Burn it in charcoal fire, and Hou Tongchi, with iron wok and wok fish as the first fire, with the tail in the right position, dip it in a basin, and stop if there is no tail." When in use, put the water bowl flat in a windless place, and the fish will float on the water surface, and its first direction will always be noon. " This is an artificial magnetization method, which uses the earth's magnetic field to magnetize the iron sheet. That is, the red-hot iron sheet is placed in the direction of the meridian. The molecules inside the red-hot iron sheet are in a relatively active state, which makes the iron molecules arrange along the direction of the earth's magnetic field and achieve the purpose of magnetization. This arrangement can be fixed quickly by dipping it in water, and the degree of magnetization can be increased by slightly tilting the fish tail downward. The invention of artificial magnetization method has played a great role in the application and development of compass. It is also a great event in the history of the development of magnetism and geomagnetism. Shen Kuo of the Northern Song Dynasty mentioned another method of artificial magnetization in Meng Xi Bi Tan: "The Fang family can guide with a magnet." According to Shen Kuo, the technicians at that time rubbed the sewing needle with a magnet, which made the needle magnetic. From the present point of view, this is a method of using the magnetic field of natural magnets to make the arrangement of magnetic domains in the steel needle tend to a certain direction, thus making the steel needle show magnetism. This method is simpler than geomagnetic method, and the magnetization effect is better than geomagnetic method. The invention of friction method is not only the earliest in the world, but also creates conditions for the emergence of practical magnetic director.
Shen Kuo also talked about various phenomena during the magnetization by friction method in the supplementary talk of Meng Xi Bi Tan: "If you use a magnet to rub a tit for tat, you will be sharp and always guide, and some people will point to the north, and they are not afraid of stones ... On the contrary, there should be differences between the north and the south, and you have not studied them deeply." That is to say, after rubbing the sewing needle with a magnet, tit-for-tat sometimes points to the north. From the present point of view, all magnets have two poles, N and S. When magnetized, the orientation of sewing needle is different, so the direction after magnetization is different. But Shen Kuo didn't know this truth. He recorded this phenomenon truly and frankly admitted that he didn't think deeply. In the hope that future generations can further explore.
Shen Kuo introduced four ways to install the magnetic needle:
1. Water float method-put a few rushes on the magnetic needle to float on the water, and you can indicate the direction.
2. bowl lip rotation method-place the magnetic needle on the edge of the bowl mouth, and the magnetic needle can rotate to indicate the direction.
3. nail rotation method-put the magnetic needle on the fingernail. Because the nail surface is smooth, the magnetic needle can rotate freely to indicate the direction.
4. wisp hanging method-paint some wax on the middle of the magnetic needle, stick a silk, and hang it in a windless place to indicate the direction.
Shen Kuo also compared the four methods. He pointed out that the biggest disadvantage of water floatation is that the water surface is easy to shake, which affects the measurement results. Bowl lip rotation and nail rotation are flexible because of low friction, but easy to fall off. Shen Kuo emphasized the hanging method, which he thought was an ideal and practical method. In fact, the four methods pointed out by Shen Kuo have summarized the two systems of compass devices so far-water needle and dry needle.
Meng Xi Bi Tan is a book about ancient Chinese science and technology written by Shen Kuo (131-195), which talks about some problems of magnetism and compass.
In the Southern Song Dynasty, Chen Yuanliang introduced the making method of another kind of guide fish and guide turtle in Shi Lin Guang Ji. This kind of fingerless fish is different from that recorded in the book "General Introduction to the Martial Classics". It is carved into a fish shape with wood as big as a finger. A natural magnet is placed in the belly of the wooden fish, and the S pole of the magnet points to the head of the fish. After sealing it with wax, a needle is inserted from the mouth of the fish to become a fingerless fish. Float it on the water, a fish head guide, which is also a kind of water needle.
The guide turtle was a popular new device at that time. A natural magnet was placed in the abdomen of the woodcut turtle, a smooth hole was dug under the abdomen of the woodcut turtle, and it was aligned and placed on a bamboo nail with a sharp top that stood upright on a wooden board, so that the woodcut turtle was placed on a fixed and freely rotatable fulcrum. Because the friction at the fulcrum is very small, the wooden turtle can rotate the guide freely. At that time, it was not used for navigation, but for illusion. But this is the forerunner of the drought compass that appeared later.
The guide turtle was invented not later than 1325. The wooden block is carved into a turtle shape, and a magnet is embedded in the center of the turtle's abdomen. The wooden turtle is placed on a pointed upright, and when it is at rest, it points north and south respectively.
compass positioning
to determine the direction, in addition to the compass, it is necessary to have an azimuth dial to cooperate. When the compass was first used, there may not be a fixed azimuth disk. With the need of azimuth measurement, a compass with magnetic needle and azimuth disk integrated appeared. Compasses include compass for geomancy, water compass and drought compass.
the azimuth disk is still 24 directions, but the disk has evolved from square to round. In this way, just look at the position of the magnetic needle on the azimuth plate and you can determine the azimuth. In the Southern Song Dynasty, Zeng Sanyi recorded the relevant literature in the Record of Words: "The snail either has a meridian needle, or uses a meridian needle to sew between the needles." This is the earliest document about the compass. The "ground snail" mentioned in the literature is the ground snail, which is also the compass. The knowledge of magnetic declination has been applied to the compass in the literature. This kind of compass not only has the meridian needle (the magnetic needle that determines the direction of the north and south poles of the geomagnetic field), but also the meridian needle (the geographical direction of the north and south poles determined by the sun shadow). The included angle between these two directions is the magnetic declination.
Twenty-four directions are carved around the disk surface, and water is filled in it. The magnetic needle crosses the lamp grass and floats on the water surface.
It is now known that the two magnetic poles of the earth are only close to the geographical north and south poles, but do not coincide. The magnetic needle points to the earth's magnetic pole rather than the geographical north and south poles, so the magnetic needle points to a slight deviation instead of the due south and north direction. This angle is called magnetic declination. Because the earth is almost spherical, the magnetic needle will tilt downward when pointing to the magnetic pole, and there is an angle with the horizontal direction, which is called the magnetic inclination angle. The magnetic declination and inclination are different at different locations. Wu Jing Zong Yao, written in the Northern Song Dynasty, paid attention to the use of magnetic inclination when talking about making compasses by geomagnetic method. Shen Kuo talked about the incomplete compass in Mengxi Bi Tan, which is often slightly to the east. The existence of magnetic declination is pointed out. The discovery of magnetic declination and magnetic inclination makes the compass point more accurately.
application of magnetic properties
once invented, the compass was quickly applied to military affairs, production, daily life, topographic survey and other aspects, especially to navigation. The application of compass in navigation has a gradual development process. In Ping Zhou Ke Tan, which was written a little later than Meng Xi Bi Tan, it is recorded: "A boat master knows geography, but he watches the stars at night, the sun by day, and the compass by gloom." This is the earliest record of using a compass in the history of world navigation. It is pointed out that the compass was only used when the sun, the moon and the stars were out of sight, which shows that the compass was not skilled when it was first used. More than 2 years later, Xu Jing's "Xuan He Feng Zhi Gao Li Tu Jing" has a similar record: "Only look forward to the stars, and if you are gloomy, use the guide to float the needle to slap the north and south." In the Yuan Dynasty, the compass became the most important instrument for navigation at sea. I navigate with a compass day and night, sunny or cloudy. Moreover, the connection diagram of compass needle position in different navigation places using compass navigation is also compiled, which is called "needle road" When a ship goes to a certain place, the direction of the needle position and the route along the way are clearly marked as the basis for navigation.
The invention of the compass is the result of ancient ancestors' observation and research on magnetic phenomena. In the process of observing and studying magnetic phenomena, ancient ancestors further understood the properties of magnetism and tried to apply these properties more. Legend has it that when Qin Shihuang built Epang Palace, one of the palace doors was made of magnets. If an assassin passes by with a sword, he will be immediately caught by the guards. There are many such stories. The Biography of Ma Long in the Book of Jin records that Ma Long led his troops westward into Gansu and Shaanxi, and piled up magnets on both sides of the narrow road that the enemy had to pass through. When the enemy soldiers in real armor passed by, they were firmly absorbed and could not move. Malone's soldiers wear rhinoceros armour, and magnets have no effect on them, so they can move freely. The enemy thought that the magic weapon would retreat without fighting. The Records of Foreign Bodies in the Eastern Han Dynasty recorded that there were some reefs and shoals around the South China Sea Islands that contained magnets, and the magnets often attracted ships that were "occluded by iron leaves", making it difficult for them to get out.
During the Wei, Jin, Southern and Northern Dynasties, our ancestors had a lot of knowledge about the nature of magnets. Even Cao Zhi, a poet at that time, used "a magnet attracts iron, but gold is not connected" in Jiao Zhi's poems. Sentence. It can be seen that he also understands the nature of magnets. Tao Hongjing of the Northern and Southern Dynasties in the Liang Dynasty put forward the method of magnetic measurement in "A Record of Famous Doctors". He pointed out that excellent magnets are produced in the south, which are very magnetic and can attract three or four iron needles, so that several needles can be hung on the magnets end to end. Magnets with stronger magnetism can attract more than ten iron needles and even hold one or two Jin of knives. Tao Hongjing not only pointed out that there are strong and weak magnetism, but also pointed out the measurement methods. This may be the earliest record of magnetic measurement in the world.
Chinese ancestors' research and understanding of the nature of magnets is the basis for the invention and development of compasses.
China invented two methods of artificial magnetization in the Northern Song Dynasty: one is to rub steel needles with natural magnets as Shen Kuo said, and the other is to magnetize steel by using the earth's magnetic field.
People put a magnetized steel needle through a few rushes and put it in a bowl filled with water, so that it can float on the water to point out the direction for ships. This is the earliest instrument in the world-the compass. And many animals have learned to use the earth's magnetic field to tell the direction before us.
gunpowder
gunpowder is one of the four great inventions in ancient China. Because it is made of a mixture of saltpeter, sulfur and charcoal, and at that time, people used these three things as medicines to treat diseases, so it was named "gunpowder", which means "fire medicine".
since the Qin and Han dynasties, alchemists have used sulfur, saltpeter and other substances to make alchemy, and got inspiration from the accidental explosion. After many times of practice, they found the formula of gunpowder. During the Three Kingdoms period, there was a clever technician, Ma Jun, who wrapped gunpowder in paper.