Mahjong friends had a little quarrel about who should be held responsible for death two days after returning home.
Wang Zhenduo’s related view is that the invention of the compass was no earlier than the Song Dynasty. This view is reflected in a series of his research results. As stated in the article "Sinan, Compass and Compass (Part 1)": "From the weekend to Li Tang, the ancients called 'Sinan' or 'guide' an instrument for identifying directions. It is easy to carry and Testing is just like a compass. Wang Zhenduo believes that portable compass-like instruments have appeared in the Tang Dynasty, but they are by no means a compass. Wang Zhenduo regards this kind of object as a transitional form of the compass. Wang Zhenduo does not clearly judge the specific time when the compass was invented. Q, due to lack of materials and considerations of scientific rigor, he did not make a conclusion easily. He said in "Sinan, Compass and Compass (Part 2)": "The (Compass) Fish Method is definitely earlier than the (Compass) Needle Method. Half a century has passed, but the relationship between the two has still to be discovered and explained by historical evidence. "It is said under this circumstance. In addition, in the same paper, it is said: "In ancient China, artificial magnet compasses were made by artificially transmitting magnetism through sewing steel needles. The historical evidence of this has not yet been discovered. It can be seen as early as the 11th century. "This is based on Shen Kuo's "Mengxi Bi Tan · Magazine One" and "Meng Xi Bi Tan Supplement" in the Northern Song Dynasty. These two articles record this kind of artificial magnet compass to form an artificial magnet. In addition, Wang Zhenduo In this article, he criticized the misunderstanding that the Tang Dynasty monks and his party had noticed the difference between the direction of the magnetic needle and the North Pole, as stated in "China Studies" by the Englishman Alexander Wylie. Finally, he solemnly concluded: " According to the records of the deflection of the compass needle in China, no historical evidence has been found earlier than "Mengxi Bi Tan". It is recorded as "slightly to the east" in Zunzhong, and Kou Zongshuang records that it is "slightly to the east", which refers to the deflection angle of the compass needle. "This is why Wang Zhenduo cannot have a precise understanding of the time when China's magnetic declination was discovered due to so-called limitations of materials. Regarding the age of the invention of the compass, Wang Zhenduo only gave a rough guess. In "Sinan, the Compass and the Compass ( In), Wang Zhenduo said: "The era of the invention of the compass is based on the magnetic needles used by ships in "Pingzhou Ke Tan" and Shen Kuo's claim that the Fang family made magnetic needles. It is believed that its creation must have been early. "The invention of the compass should be the result of slow improvement over a long period of time, and the forms of different periods should also appear in different forms. Mr. Wang can only give a time interval. [4]
As he stated in the book: "But there were several technological transitions from Sinan Yi to the compass, and these transitions occurred from the Wei, Jin, Southern and Northern Dynasties to the Tang Dynasty. "His judgmental conclusion does not have much material support. But this conclusion is generally correct. Mr. Pan Jixing, like Mr. Needham, used the words "tadpole, toad, frog" in Cui Bao's "Ancient and Modern Notes" ) Ziye, one is Xuanzhen, the other is Xuanyu. "Looking at the transition from the spoon to the needle." He said: "The combination of the magnetic needle in the air and the azimuth disk was used in the Shanxi, Southern and Northern Dynasties, and it can indeed guide the needle, thus realizing what Mr. Needham said from the spoon to the needle." The transition from needle (spoon to needle). "Mr. Pan Jixing also made a conclusion on the emergence of the water compass in the same book. He said: "There is evidence that the makers of the Kanyu compass in the Tang Dynasty in the 9th century had already taken this decisive step. "On the same page, he once again emphasized: "The Jin, Southern and Northern Dynasties began to make technological improvements to Sinan, and in the late Tang Dynasty, the transformation from Sinan to Compass was completed. The people of the Northern Song Dynasty enjoyed these technological achievements and carried them forward. The historical development context It should be so. "Further elaborated on the development of the compass. Based on Mr. Needham's research, Pan Jixing absorbed some of Mr. Wang Zhenduo's views and redefined the time and process of the invention of the compass, although there are still some inaccuracies. However, in general, it is a progress in the history of science and technology. Other scholars either made surprising conclusions because they did not have new materials, or they made new conclusions based on only a certain fragment of material because of insufficient materials. Generally speaking, they are not convincing to everyone, and their influence is not very great." The origin of the compass is concluded to be in the Tang Dynasty. Regardless of whether this conclusion is correct or not, this conclusion cannot be reached at all based on this material alone.
[4]
Point 3
In the collection of Chengdu folk collectors, a jade (stone) artifact of great academic research value was discovered. It is made of seven pieces. It is made up of spliced jade (stone) boards, with graphics on the front and ancient characters on the back. Especially in the middle of the 4th jade (stone) board, there is a circular pattern on which a half "earth" is placed. thing. On the top of this "earth" (the North Pole) there is a small hole 4cm in diameter, with a jade (stone) compass inserted in it. On the circular pattern, there are "east", "south", "west" and "north". "Four ancient characters. According to the analysis of existing subject expertise, these four ancient characters are the same as the azimuth characters for "east", "south", "west" and "north" on the compass we use today when doing geological mapping, except for the character "东" In addition, the other three characters "South", "West" and "North" are different from the oracle bone inscriptions. The discovery of the compass on Sanxingdui jade (stone) artifacts is very important. The view that the compass first appeared in the Spring and Autumn Period and the Warring States Period will be completely overturned. The Yellow Emperor's invention of the compass has been mentioned in the literature, but so far it is only speculation and has not been Archaeological objects were found, and the discovery of compasses on jade (stone) vessels in the Sanxingdui area pushed the discovery history of the Chinese compass to the Fuxi era. The compass found in Sanxingdui is made of jade (stone) and does not rotate, so it is symbolic. [5]
Early form editing
In China's azimuth culture, it went through the astronomical method of positioning, then the magnetic method to make the Sinan, and finally the Sinan evolved into three compasses. stage, followed by the continuous improvement of position determination technology. [4]
Sinan
Sinan is the earliest magnetic pointing device. The name "Sinan",
Figure 1 - Sinan model (restored by Wang Zhenduo)
Figure 1 - Sinan model (restored by Wang Zhenduo)
It began in the Warring States Period (AD 475 BC - 221 BC) and ended in the Tang Dynasty (618 AD - 907 AD). Because of the continuous evolution of Sinan's ancient meaning, it has an indissoluble bond with a series of ancient inventions. [1]
The earliest document recording Sinan is "Guiguzi", which writes: "When a Zheng man takes jade, he must carry Sinan's car, so he is not confused." (Mou Chapter) From It can be seen from the records in "Guiguzi" that when Zheng people went to "fetch jade", they had to take Sinan with them in order to avoid getting lost.
Among the documents mentioning Sinan, Wang Chong’s account is the most important. He clearly pointed out: “When Sinan’s ladle is thrown to the ground, it is the guide.” (Ying Pian) Among them, “ "Ladle" refers to a spoon. Sinan with this "guide" performance should be a magnetic pointer. However, the "land" here refers to the "territory" in the ancient weapon disk. The mechanical disk was invented during the Qin and Han Dynasties and was used for games or divination. There are 24 directions engraved around the "territory", and a symbol symbolizing the Big Dipper is engraved in the center. Wang Zhenduo, a famous modern historian of science and technology and expert in replicating cultural relics in China, successfully restored Sinan of the Han Dynasty based on these records (as shown in Figure 1).
Figure 1 Model of Sinan (restored by Wang Zhenduo). No actual object of the spoon-shaped Sinan has been unearthed.
Figure 2 - Han Dynasty stone relief hidden in the Rietburg Museum in Zurich
Picture 2 - Han Dynasty stone reliefs in the Rietburg Museum in Zurich
However, there are images similar to the spoon-shaped image of Sinan on the Han Dynasty portrait stones (as shown in Figure 2), which indicates that Wang Chong’s record should be Believable. In this stone statue, it can be seen that the main body of the picture is a magician and acrobats performing, and the group of people above are the aristocratic audience. There is a long-handled spoon suspected to be Sinan's on the small square platform in the upper right corner (see the inset outside the picture). ), a man is kneeling observing it.
Figure 2: Han Dynasty stone reliefs stored in the Rietburg Museum in Zurich (this picture is quoted from Joseph Needham's "History of Chinese Science and Technology Physics Volume"). Judging from the materials left behind, magnets are used to indicate polarity. The Sinan is the earliest form of magnetic pointing device. [6]
The emergence of magnet orienting devices has enabled people to shift from the passive orientation of observing celestial bodies to the active orientation of geomagnetic orientation. The earliest human magnet orientation device was the Sinan made of natural strip magnets. It appeared at the end of China's Warring States Period (3rd century BC) and was further developed in the Han Dynasty.
The emergence of Sinan Yi is of great historical significance, because it is a new type of guiding device made of magnetic principles that are completely different from astronomical orientation principles. It can work day and night under any weather conditions, quickly point out the direction, and is easy to operate and easy to carry. [4]
Originally, "Sinan" refers to the meter rod of photometry. For example, "Han Feizi·Youdu Pian" says, "Therefore, the previous kings set up Sinan to direct the morning and evening." "Duan morning and evening" means to align the east and west, which is extended to determine the direction of east, west, north, and south. "Li Sinan" comes from the "Li Zhong" in the oracle bone inscriptions of the Yin and Shang Dynasties and the "Li Chao Xi" in the Warring States Period. They both mean to set up a table to measure the shadow of the sun. [1]
Magnetic spoon
The magnetic spoon is a spoon-shaped pointing device made of natural magnet. When it was discovered, its shape was based on the Big Dipper, and its name was still used. "Si Nan". There are at least four records in "Guiguzi", "Lunheng", "Xuanlan Fu" and "Piao Fu" that can be inferred as a magnetic spoon in the ancient text "Si Nan". "Book of Song·Li Zhi" quoted "Guiguzi" and said: "When Zheng people take jade, they must carry Siman, so they are not confused." "Guiguzi·Mou Pian" was written in the Western Han Dynasty at the latest, and may be a pre-Qin book. The legend that "anyone who takes jade must carry Sinan" hints at the connection between the magnetic spoon and the jade industry. The difficult-to-process magnetic spoon should be the masterpiece of a master of jade craftsmanship.
The "Lunheng Shiying Pian" written by Wang Chong of the Eastern Han Dynasty said: "Sinan's spoon is thrown to the ground, and it guides the ground." The "di" in the sentence is generally interpreted as "territory", also It may be that the word "pool" was misspelled. This sentence should be interpreted as: When the spoon-shaped Sinan is placed on the "turf" (or put into a container containing an appropriate amount of liquid (such as mercury)), its spoon handle will automatically point to the south.
After that, the "Xuanlan Fu" written by Xiao Yi, Emperor Yuan of Liang Dynasty, said: "Seeing Lingwu Zhanxun, watching Sinan waiting to leave." Tang Wei Zhao's "Piao Fu" said: "Pumping the wine pulp, If you look up to the North (Beidou) and make a difference; if you play well, you can learn from the south. "The function and shape of the south (magnetic spoon) were introduced again.
Although the actual magnetic spoon has not been discovered so far, there are at least two cultural relics related to it. The first is an Eastern Han Dynasty portrait stone from 114 AD stored in the Rietberg Museum in Zurich, Switzerland. In the upper right corner there is a person observing something that may be "Sinan's Spoon". The second is an ancient jade article called "Sinan Pei" recorded in the first volume of Na Zhiliang's "General Explanation of Jade Articles". This jade article is "no more than an inch long. One end is cut into a small spoon, the other end is cut into a small round plate, and there is a cross in the middle. Wear it. "The production date of "Sinan Pei" is unknown, and it is speculated to be from the Tang Dynasty.
In addition to the above-mentioned watches and magnetic spoons, Sinan is also the name for compass, compass boat and time clock. The "Sinan car" mentioned in "Xijing Miscellaneous Notes" written by Ge Hong from Jin Dynasty is a semi-automatic mechanical device compass car. "Song Book·Li Zhi" records: "There was also a guide boat in the Jin Dynasty." Ren Fang of the Southern Dynasty's poem "Feng He Climbs Jingyang Mountain" said: "The running whale spits out the waves, and Sinan moves lightly." Sinan in the poem. It refers to the guide boat in the royal garden. However, how the "guide boat" navigates is still a mystery. Du Fu, a great poet of the Tang Dynasty, wrote a poem about "Chicken": "The air flows between the pavilion and Yujing, and the Wu Gorge leaks out to the south." This means that at midnight, the poet just heard the sound of Simon telling the time. [1]
The invention of the magnetic needle
The invention of the compass should be the result of slow improvement over a long period of time, and the forms of different periods should be represented by different forms. form appears. In the Tang Dynasty, the Kan Yu family was quite active and began to emphasize the choice of direction. Finding a pointing device that was more convenient than a magnetic spoon became a top priority. So the iron fish or tadpole-shaped iron pointing device and the water-floating magnetic needle came into being.
Qiu Yanhan, a Shanxi Kanyu master who was active in the Kaiyuan period of the Tang Dynasty (713-741), was praised by later generations of Kanyu masters as the earliest straight needle among the three needles of Kanyu (front needle, suture needle and middle needle). The founder of law. Zhu Quan, king of Ningxian in the Ming Dynasty and a master of science and technology, said in his "Secret Book of Divine Machinery": "Acupuncture has not been transmitted since ancient times. It was first made by Xuanzhen in the past." Xuanzhen is the Taoist Zhang Zhihe (about 730-about 810), his Taoist name was Xuan Zhenzi, and he wrote "Xuan Zhenzi" in twelve volumes, three of which remain. It is known from this fragment that he was good at physics, but no records directly related to the compass or acupuncture were found.
However, this Taoist name can't help but remind people of the old title of Jin Cui Bao's "Annotations on Ancient and Modern Times" where tadpoles are called "Xuanzhen". The article says: "The shrimps and tadpoles are called tadpoles, one is called Xuanzhen, and the other is called Xuanyu. They are round in shape and have a big tail. When the tail is taken off, it is born from the feet." There is a similar description in Ma Zhen's "Annotations on Ancient and Modern China" written in the tenth century. record. This record seems to connect the invention and application of the magnetic needle with the guide fish in terms of shape and performance.
About the preparation method of guide fish, it can be found in "Wu Jing Zong Yao" compiled by Zeng Gongliang and others in the Northern Song Dynasty using previous materials. The method stated in Volume 15 of the first volume of "Wu Jing Zong Yao" is: "Cut it with a thin iron leaf, two inches long and five minutes wide, with the head and tail sharp like a fish shape, place it in a charcoal fire, wait until it becomes red, and use an iron pin Put the head of the fish out of the fire, dip it in the water basin with its tail facing the sub-position, and stop it when the tail is gone." This method uses the earth's magnetic field to magnetize the iron piece, and knows that the fish-shaped iron piece is slightly downward. Tilt is beneficial to magnetization, and the effect of what is called magnetic inclination in modern science has actually been discovered. When used, the guide fish floats on the water surface, which is consistent with the principle of water-floating magnetic needles.
The method of making water-floating magnetic needles was first seen in Volume 24 of "Mengxi Bi Tan" written by Shen Kuo of the Northern Song Dynasty. The article said: "The Fang family rubs the needle with a magnet, and it can guide." This kind of Fang family The steel needle magnetization method summarized in practice was published to the world by Shen Kuo, which effectively promoted the application and popularization of magnetic needles in the two fields of navigation and navigation. The compass has entered the stage of practical magnetic needles, and research on device methods has been put on the agenda. Shen Kuo comprehensively studied and compared the advantages and disadvantages of the "water floating" method, the "finger claw" method, the "bowl lip" method and the "wisp hanging" method, and believed that the "wisp hanging" method was the best. "The method is to take a single cocoon strand from a new paper, apply wax with mustard seeds, and attach it to the waist of the needle. Hang it in a windless place, and the needle will always guide." This similar method is used for small magnets suspended in modern magnetometers. . The accuracy of the magnetic needle pointer is not the same as that of Simon and the guide fish. Therefore, the invention of the magnetic needle quickly led to the discovery of magnetic declination.
The "Guan Shi Geography Zhi Meng·Eighth Interpretation" written in the troubled times of the Five Dynasties said: The magnetic needle "is light in body and the diameter it points to must respond to the call of a qi. The earth scale is in the middle and the square scale is biased, which is better than Xuanyuan." The record is still in the Xingxu Dinggui." The author believed that the magnetic declination in the Xuanyuan and Huangdi era was still in the direction of "Xing (Wu) Xu (Zi) Ding Gui", and at that time "the needle pointed at Kanli to determine the boundary between Yin and Yang, and the grid was biased toward Ren and Bing to explore the end of Tianjin." The declination becomes 15° south by east.
Due to the mystery of Kanyu art, Kanyu works of the Tang and Song Dynasties in China influenced each other during their circulation, with additions and deletions. It is necessary to sort out the invention and discovery of the magnetic needle, magnetic declination and even the compass from many early Kanyu works. It is not an easy task in this era. However, the discovery of magnetic declination in the "Fu Yuan Zong Lu" volume compiled by Yang Weide, the Si Tianjian of the Northern Song Dynasty in the first year of Qingli (1041), set a lower limit. The book says: "When selecting the guest host, it is advisable to take the four straight points without any difference. The Bingwu needle should be taken at its right place, and the center should be squared, so that it is square and straight." Here is a clear record of the "Bingwu needle", That is what Shen Kuo, a later generation, said in Volume 24 of "Mengxi Bi Tan" that the magnetic needle "often tilts slightly to the east, but not completely to the south." In the West, it was not known until the 13th century that the magnetic needle tilted south. When Christopher Columbus (1451-1506) crossed the Atlantic Ocean in 1429, he officially measured the phenomenon of magnetic declination. [1]
A Yuan Dynasty water float compass porcelain bowl was discovered in China. In 1959, two large Cizhou kiln white-glazed brown flower bowls were unearthed from the Yuan Dynasty tomb in Ganjingzi, Lushun, Liaoning. Two concentric circles were painted on the bottom of the large bowl, and three points were painted side by side in the circle, with a line connecting them in the middle. At first glance, this shape looks like an irregular "王" character, so it is called "Wangzi pattern bowl". There is another word "needle" written in ink on the outer bottom of the bowl. Research by science and technology historian Mr. Wang Zhenduo has confirmed that this kind of bowl is the needle bowl used to indicate directions during navigation. How to use it is as follows: a magnetic needle threaded on the float floats on the water surface of the needle bowl, and the "king"-shaped mark on the inner bottom of the bowl helps to indicate the direction. First, align the thin line in the character "王" with the center line of the ship. If the ship turns, the magnetic needle will form an angle with the thin line, thus indicating the angle of the course shift. Similar bowls have been found in Yuan Dynasty cellars in Tuzhaolin Village, Jiangsu Province, and in Yuan Dynasty shipwrecks on the Zhanghe River in Cixian County, Hebei Province.
[7]
The invention and spread of the compass to the West
After the advent of the magnetic needle, it was used for navigation and navigation. In order to be easy to use and read, coupled with the discovery of magnetic declination, higher requirements were placed on the skills of using the compass. The Fang family first combined the magnetic needle with the indexing plate to create a new generation of compass - the compass. However, on some occasions, the water-floating magnetic needle in the bowl is still used, so Volume 24 of Shen Kuo's "Mengxi Bi Tan" says "the water floats and shakes a lot". Special needle bowls for compasses without graduations from the Yuan Dynasty have been unearthed in Luda, Jiangsu, Hebei and Liaoning. When the ship was still using floating needles and needle bowls, Kanyu Compass ran far ahead.
Archaeological data show that
The figurines of Immortal Zhang and the dry compass
The figurines of Immortal Zhang and the dry compass
The Kanyu family chose two tombs. The fourteen-way representation began around the end of the Tang Dynasty. He Pu of the Southern Tang Dynasty presided over the construction of Hui City, and he also used the twenty-four-way representation when looking at Feng Shui. He Pu's "Lingcheng Jingyi" "Liqi Zhangzhengjue" written by He Pu said, "The earth is positioned in the eight directions to determine the path of the universe and the map, so Zhengziwu is used as the territory, and it is located inside to correspond to the reality of the earth." Heaven. The twelve divisions are divided into two parts, Zheng Lian Du and Zheng Lian Du. Therefore, Renzi and Bingwu are used as the sky disk, which is placed outside to correspond to the emptiness of the sky. "There is an almost identical text in the "Regulating Qi Chapter" of "Jiutian Xuannv Qingnang Haijiao Sutra" written by an unknown author, and the two should come from the same source.
The compass was called "earth snail" in ancient times, "Diluo". The article "Ziwu Needle" in "Yin Hua Lu" written by Zeng Sanpin of the Southern Song Dynasty (written around 1200 AD) says: "Diluo may have Ziwu Zhengzhen, or Zirenbing Wuzhong needle. "Zeng Sanpin was from Linjiang, Yuxiajiang, Jiangxi (now Xiqingjiang, Jiangxi). In Linchuan, Jiangxi, not far from Xiajiang, the world's earliest Kanyu dry compass model was unearthed in 1985, which can be compared with "Yinhualu" " records mutually corroborate each other. In May 1985, two porcelain servants with the inscription "Zhang Xianren" on the bottom of the seat were unearthed from the Southern Song Dynasty Zhu Jinan's tomb in Linchuan, Jiangxi [7 ], holding a compass in his left hand. It is worth noting that the magnetic needle of this compass is fundamentally different from the magnetic needle of the water compass. The middle part is enlarged in the shape of a rhombus, and there is an obvious round hole in the center of the rhombus, which clearly indicates that this is a type of drought supported by a shaft. Compass.
China’s magnetic needle and compass spread westwards through land and water, and had a great impact on the process of human civilization. In the past, historians believed that the magnetic needle in the water and the water compass were of the same origin. It is a Chinese invention, but the dry compass was invented in Europe and was introduced to China via Japanese ships in the 16th century. Now the Linchuan compass proves that the invention of the dry compass also belongs to China. [1]
The original form of magnet refers to polarity and magnetic director
As for the understanding and application of magnet's ability to attract iron, it is said that the magnet door of the Qin Palace can prevent assassins with iron blades Enter. There are many descriptions of the phenomenon of magnets attracting iron, such as "Lu Shi Chun Qiu" written during the Warring States Period, "Huainan Zi" written during the Western Han Dynasty, and "Lunheng" written by Wang Chong of the Eastern Han Dynasty. These authors all mentioned the phenomenon of magnets attracting iron. , objects such as tortoiseshell and amber can attract certain light and small objects. Wang Chong pointed out that these phenomena are the function of "induction" (a view of action at a distance), but he does not seem to know the difference between electric induction and magnetic induction. It is made of natural magnet. To invent the compass, it is necessary to study the polarity of the magnet [6]
Description of magnetization technology and magnetic deflection phenomenon
Magnetization technology in the Northern Song Dynasty. Breakthroughs were made, and these technologies accelerated the popularity of magnetic pointing devices and led to new evolutions in pointing devices.
Zeng Gongliang's "Wu Jing Zong Yao" mentioned a new type of magnetic pointing device. - "Guide Fish". At the same time, we can also see that the key to making a guide fish is the magnetization of iron. Zeng Gongliang's description is: cut from a thin iron leaf, two inches long and five minutes wide, with a sharp fish-shaped head and tail, and set on a charcoal fire. When it is cooked, wait for it to turn red. Use an iron sword to hold the fish head out of the fire. Dip the tail into the basin and cut it into pieces. (Volume 15) Zeng Gongliang actually used the geomagnetic field to cut the fish into pieces. Magnetizing a shaped iron piece is a breakthrough in the history of mankind seeking new magnetization technology. However, since it must be placed on the water surface during use, it is also important to note that the iron piece should be as thin as possible.
The magnetism of guide fish is very weak. As a "natural" flaw, the round fish head also limits its pointing accuracy. While this simple magnetization technique makes it much easier to create guide fish, its shape causes similar drawbacks to the spoon-shaped guide fish.
Similarly, the practical magnetization technology was also recorded in "Mengxi Bi Tan" by Shen Kuo, a contemporary of Zeng Gongliang. He wrote: "The Fang family uses magnets to sharpen the needle point, which can guide the guide. However, it is often slightly to the east and not completely south." (Volume 24) This shape is easy to popularize and simple, and the magnetization effect is also quite good, especially, It produced another breakthrough in improving the shape of the pointing device - the needle shape. Pointing with a needle, its pointing accuracy can be greatly improved. In this way, Sinan evolved into a compass, and this kind of compass became more popular. Undoubtedly, this is the most important improvement in the shape of the magnetic director.
As the pointing accuracy of the pointer has been improved, people soon noticed when using the compass that the direction it pointed was sometimes not due south. This is the phenomenon of magnetic deflection - "However, it is often slightly eastward, but not completely southward." South Ye".
In fact, in the "Fu Yuan Zong Lu" written in the first year of Qingli (1041), Yang Weide, who was slightly earlier than Shen Kuo, had recorded the existence of the compass and magnetic declination. He wrote: "To ensure that there is no difference in the four straight directions, we should take the Bingwu needle. Place it in the right place, check it in the middle, and get the straightness." (Volume 1) The "needle" mentioned here is the magnetic needle, and "Bingwu needle" "Needle" means that when the magnetic needle is at rest, the direction pointed by the needle is the combination of the C position and the midday position among the 24 directions, which is about 7.5° south by east. This is consistent with Shen Kuo's "slightly eastward", but Yang Weide's statement is earlier and the description is more accurate.
Kou Zongyi, who was slightly later than Shen Kuo, also mentioned in the "Compendium of Materia Medica": "A magnet and a sharpened needle can guide the guide, but it often skews to the east and does not go all the way to the south. The method is to use the new method. There is a single thread in the middle, and half a mustard seed is applied to the waist of the needle. If it is hung down in a windless place, the needle will always be in the C position. "(Volume 5) This passage talks about the magnetization of the compass, the discovery of the magnetic deflection phenomenon, the erection of the compass, and the use of the Five Elements theory to briefly explain the reason why the magnetic needle points. Here, Kou Zongyi used the "water float method", which is somewhat different from Shen Kuo. This also shows that people were still exploring forms and making different attempts at this time. As early as the "Guan Shi Geography Guide" written in the late Tang Dynasty, we can read in this document: Magnet is the mother's way, and needle is the iron's death. The nature of mother and child is due to this sense and communication; the nature of being killed is due to this recovery and completion. The body is light and narrow, and the pointer must be pointed. In response to the call of Qi?. From this passage, we can see that the magnetic declination it describes is about 15° south by east. This shows that the discovery of geomagnetic deviation may be earlier than the Song Dynasty. Another early document that mentions geomagnetic deviation is "Jiutian Xuannv Qingnang Haijiao Sutra", which was written around the second half of the 10th century.
Wang Jia (the founder of Kanyu School in Fujian), who was roughly contemporary with Shen Kuo, also mentioned magnetic declination. In one of Wang Ji's poems, he wrote: "The needle is clear between the virtual and the dangerous, and the three roads in the south are on the three vehicles." What is mentioned in the previous sentence here is obviously the north-south direction of celestial coordinates, but by observing the geomagnetic compass, you will find that the "spread" range of the southern constellations is so wide that the two magnetic declinations and the due south of the celestial coordinates are The three "south" directions are included in it. Therefore, the specific value of his involvement in magnetic declination cannot be completely determined, but his record of geomagnetic deflection phenomenon shows that Feng Shui masters attach great importance to the study of geomagnetic deflection phenomenon. Wang Guan was a famous Kanyu scholar, and his main works were written between 1030 and 1050.
The "Yin Hua Lu" written by Zeng Sanyi in the Song Dynasty in 1189 mentioned that there must be a certain area on the surface of the earth where the magnetic declination is zero. Zeng Sanyi's point of view is very insightful. In fact, there is indeed a zero magnetic declination line. Even so, he only offered a valuable guess. In the 16th century, people in the Ming Dynasty made a sudden discovery that the magnitude of the magnetic declination was different in different locations; only in the 18th century did clear records appear that the magnitude of the magnetic declination also changed with time.
[6]
Compass erection methods and compasses
How to erect a compass, Shen Kuo compared 4 different erection methods:
The water is swaying. It can be done on the finger claws or the lip of the bowl, and the operation is particularly fast, but it is slippery and easy to fall, so it is best not to hang like a thread. The method is to take a single cocoon strand from a new paper, apply wax with mustard seeds, and decorate it on the waist of the needle. Hang it in a windless place, and the needle will always guide the needle. This is the famous "Four Methods" of Shen Kuo. Shen Kuo took a negative attitude towards the first three methods, although the "water floating method" was a method that Zeng Gongliang had already tried. The usage method recorded in "Wu Jing Zong Yao" is to "lay the guide fish flat on the water surface to make it float." For this reason, the fish-shaped iron leaves may be slightly concave in the middle. This structure makes the iron fish float on the water like a boat. superior. Zong Yi also proposed the installation method. He pointed out: "Putting a needle across the core of the lamp and floating on the water can also guide the compass." [6]
Four methods of installing compasses tried by Shen Kuo
During the Southern Song Dynasty, new progress was made in the issue of compass erection. Chen Yuanliang of the Southern Song Dynasty described two types of compasses in "Shi Lin Guang Ji" (written between 1100 and 1250), namely the compass fish and the compass turtle. They can be regarded as the precursors of "water needle (water compass)" and "dry needle (dry compass)". The water compass (also called the floating needle compass) was developed from the guide fish in "Wu Jing Zong Yao" to the guide fish in "Shi Lin Guang Ji". Since the latter is carved from wood, it can naturally float on the water and does not seem to be afraid of the water surface. Shake, it has developed into a relatively mature structure. Since then, the water needle has been more popular, and with further improvements, the magnetic needle was threaded into small wooden strips, replacing the wood-carved fish, making it more practical. Naturally, the "guide fish" form also disappeared. The "Guide Turtle" recorded in "Shilin Guangji" was the pioneer of the dry compass in later generations. It is also popular among people because it uses bamboo nails for support, which has low friction and flexible rotation. Later, people developed it into a pivot-supported type, and this shape became an easy-to-use dry compass. In May 1985, a figurine named "Xianren Zhang" was unearthed from Zhu Jinan's tomb in Wenquan Township, Linchuan County, Jiangxi Province. He was 22.2cm tall and held a compass in his hand. The structure of this compass-like magnetic device is different from that of the Song Dynasty water-floating needle. There is an obvious round hole in the center of the rhombus-shaped needle, indicating that it adopts a pivot-supported structure. This tomb was buried in the fourth year of Qingyuan in the Southern Song Dynasty (1198). It can be seen that not long after the dry compass came out, the Chinese had developed it into a pivot-support type. [6]
Conclusion
The dry compass was later introduced to Europe via Arabia and developed maturely in Europe. The Europeans further improved this dry compass, making it very convenient to use. This improvement, although it did not increase or even "improve" the knowledge of magnetism, had a positive impact on navigation. In other words, in the process of developing navigation, the value of magnetic technology can be highlighted. Judging from the knowledge of magnetic iron attraction and finger polarity, in the early stages of the development of magnetic technology, magnetic technology was valuable to production development and navigation and navigation activities, and the improvement of magnetic technology was developed around this demand. At the same time as the development of magnetic technology, people have also accumulated some knowledge about magnetism. This accumulation process is slow, which is of course due to the seemingly simple magnetic knowledge, which is related to the understanding of the earth's (global) magnetic field. This adds a certain complexity to the problem, and it will take time and a certain kind of genius to crack this complexity; at the same time, high-level precision experiments are also expected.
In these precise experiments, two methods of magnetization technology are important. In the development of these magnetization technologies, the scientific principles that the ancients relied on were either unknown or inconsistent with modern scientific principles. Therefore, the ancients groped forward in the dark and developed through understanding of experience. Among these inventions, the invention of the shape of the compass "needle" improved the accuracy of pointing and also enabled the discovery of magnetic declination. The shape of the needle is undoubtedly of great significance, as it advances the understanding of magnetism and is beneficial to the accumulation of magnetism knowledge. Generally speaking, in the evolution of magnetic pointing devices, the continuous improvement of the shape is very important. Just like after the invention of the car, the appearance of the car has continued to change, even a big change, but this is also a gradual evolution. The exchange of magnetic pointers also includes the exchange of magnetic knowledge, which promotes the accumulation and development of "magnetic" knowledge.
This did not bear fruit until recent times. [6]
Edit of the Compass's Transmission to the West
China's magnetic needle and compass were transmitted westward by land and water, which had a significant impact on the process of human civilization. Historians believe that the water compass, with its magnetic needle floating in the water, is of the same origin as the compass and is a Chinese invention. The dry compass held by the figurine "Zhang Xianren" unearthed from the Southern Song Dynasty Zhu Jinan's tomb in Linchuan, Jiangxi Province in 1985 proves that the right to invent the dry compass also belongs to China. [1]
Although GPS is widely used in navigation, positioning, speed measurement, and orientation, because its signals are often blocked by terrain and objects, the accuracy is greatly reduced and even cannot be used. Especially in urban areas with dense buildings and forested areas with dense vegetation, the effectiveness of GPS signals is only 60%. And when stationary, GPS cannot give heading information. To make up for this shortcoming, a combined navigation and orientation method can be used. The electronic compass is designed to meet such user needs. It can effectively compensate the GPS signal to ensure that the navigation and orientation information is 100% effective. It can work normally even after the GPS signal is lost, achieving "lost stars but not direction".