Seismograph is a masterpiece created by Zhang Heng, a scientist of Han and Eastern Han Dynasties in China.
Seismographs have eight directions, namely, east, south, west, north, southeast, southwest, northeast and northwest. There is a faucet with a dragon ball in each direction, and there is a toad under each faucet. If there is an earthquake on both sides, the dragon ball in the longkou in that direction will fall into the toad's mouth, so that the direction of the earthquake can be measured.
Chinese name
Zhang seismograph
Foreign name
seismometer
inventor
Zhang heng
Time of invention
Yangjia Yuannian (A.D. 132)
use
Grasp the earthquake dynamics and general orientation
quick
navigate by water/air
Textual research on the principles of historical records and earthquake records; Other news was questioned; Experts respond to textual research on nouns.
origin
Zhang Heng lived in the Han Dynasty and the Eastern Han Dynasty with frequent earthquakes. According to the Records of Five Elements in the History of the Later Han Dynasty, there were 26 major earthquakes in the thirty years from the 4th year of Yonghe (AD 92) to the 4th year of Andi Yan Guang (AD 125). Earthquake areas sometimes reach dozens of counties, causing ground fissures and landslides, houses collapsing, rivers flooding and huge losses. Zhang Heng has many personal experiences about earthquakes. In order to master the national earthquake dynamics, after years of research, he finally invented the world's first seismograph-Hou Feng seismograph in the first year of Yangjia (AD 132). At that time, an earthquake in the western region was successfully predicted by using this instrument, which attracted the attention of the whole country. This is earlier than the earthquake history recorded by instruments in western countries 1700 years.
In November of the third year of Yang Jia, Emperor Shundi of Han Dynasty (AD 134 13 February), a dragon machine of the seismograph suddenly started, spit out a copper ball and fell into toad's mouth. At that time, people in the capital (Luoyang) did not feel any signs of the earthquake, so some people began to talk about it. Strangely, the instrument did not work. A few days later, someone in Longxi (now Tianshui, Gansu) reported that an earthquake did happen there a few days ago, so people began to believe in Zhang Heng's superb technology. Longxi is more than 1000 miles away from Luoyang, and the seismograph marks correctly, which shows that its seismic sensitivity is relatively high.
However, due to the long history, Zhang Heng's seismograph has been lost, leaving no physical objects and drawings, only some short written records.
history
Since modern times, many people at home and abroad have made great efforts to restore Zhang Heng's seismograph, and some written records about Zhang Heng and his seismograph have also been unearthed in historical documents.
Historical records of seismographs:
Ye Fan (398 -445) compiled the Book of the Later Han Dynasty based on dozens of historical works written by predecessors. Among them, "Zhang Hengchuan in the Later Han Dynasty" recorded the words 196 in the seismograph after the wind:
"In the first year of Yangjia, the seismograph after the wind was rebuilt. It is made of the finest copper, and its circular diameter is eight feet. It is covered and raised in the shape of a wine statue, a turtle decorated with seal script, a bird and a beast. All of them are pillars, eight-way, and the engine is turned off. There are eight dragons outside. The first one is a copper pill, and the next one is a toad. Open your mouth and accept it. Its teeth are cleverly made, all hidden in respect, and its coverage is endless. If there is an earthquake, the venerable master will make the dragon vomit pills and the toad will take them. The vibration was so exciting that the waiters noticed it. Although Yilong started the engine, Qige didn't move, and the air was full of places that knew about the earthquake. Test it with something, it is like a god. Since it is recorded in the book, there is nothing left. Have a taste of eLong's machine, and you won't feel anything. Scholars in the capital accused it of its absence. A few days later, we arrived, and the Longxi earthquake was beautifully shot. Since then, historians have remembered what to do. "
Zhang Heng, a scientist in the Eastern Han Dynasty
Justin (328 -376) of the Jin Dynasty recorded the seismograph after the wind in the Book of Shun Di in the Later Han Dynasty:
"As heavy as a seismograph, it is made of copper and has a circular diameter of eight feet. Shaped like a wine bottle, it is covered with dragon patterns and decorated with mountain turtles, birds and animals. The bottle is full of columns, eight on the side, and the engine is off; There are dragons in all directions outside. The first one is a copper pill, which is carried by a toad. Its teeth are skillfully made, all hidden in the bottle, stretched out, covered, thorough and boundless, if one. When the earth shakes, the toad spits pills when the dragon is launched, and the toad opens his mouth to pick it up. When the marbles are vibrating, you can know that there is a dragon machine and the other seven songs are not played, so you can know that the earthquake has never happened. If the contract is harmonious, since then, earthquake historians have taken notes and recorded this place from the side. People who come to see it are not surprising. "
Sima Biao (XX-306) in the Western Jin Dynasty recorded the seismograph of waiting for the wind in the Book of Continued Han Dynasty.
"Zhang Heng implicative, witty remarks. As a seismograph, it is made of fine copper with a round diameter of eight feet, which looks like an inclined bottle; It covers the dome and is decorated with seal script; There are eight dragons outside, with copper pills and toad bears at the head. Its engine is hidden in a bottle, endless and thorough, as one. When the earth shook, the dragon spit pills, and the toad opened his mouth to collect pills, and the sound was exciting. If the master perceives it, he will save the dragon machine. If the other seven songs are not played, he will know where the earthquake came from. If the contract is a god, look at its strangeness and not be dissatisfied. There has never been anything since ancient times. " (Excerpted from Liu Yun's Taiping Yulan Craft Department in the Northern Song Dynasty)
Among the three historical books recording the seismograph after the wind, the later Han Dynasty was about 69 years earlier than the later Han Dynasty, and the latter Han Dynasty was about 139 years earlier than the latter Han Dynasty. From the original works, the later Han Dynasty is superior to the later Han Dynasty, and the latter Han Dynasty is superior to the latter Han Dynasty.
seismic record
Seismographs can't record the time of the earthquake, let alone its magnitude. Therefore, from the perspective of modern seismology, a seismograph cannot record earthquakes, and it is not a seismograph. Some works on the history of science and technology claim that the "waiting seismograph" made by Zhang Heng in AD 132 can accurately record earthquakes, which is more than 700 years earlier than the first seismograph in the West (1856 made by Italian Luigi Palmiri). Some data also say that seismographs can "predict earthquakes". However, the records about the seismograph after the wind in the history books can only be found in the Book of the Later Han Dynasty. There are only 196 words in this record, of which only 12 words have obscure meanings and different opinions, describing the internal structure of the seismograph. Later, Xin in the Northern Qi Dynasty and Lin in the Sui Dynasty also made seismographs and left related works, but unfortunately their works were lost. Obviously, it is impossible to restore Zhang Heng's Waiting for the Ground Motion Instrument only by the simple records in the Book of the Later Han Dynasty. Today's copywriting is actually a new creation under the "constraint" of history books. However, the records in the Book of the Later Han Dynasty provide us with some useful information. First of all, a seismograph is by no means an earthquake predictor. It only works after the earthquake, but it can inform people in Beijing earlier than from the post office. It's like when we see lightning, we know that thunder is likely to be heard next, but when lightning happens, the thunder has already happened at the same time, but it hasn't reached our ears yet. Secondly, according to the propagation mechanism of seismic waves, seismographs can't be "practical and harmonious". When an earthquake occurs, the source will emit two kinds of waves: one is called P wave, which makes the object vibrate in the same direction as the wave; One is called S wave, which is shear wave. The vibration direction of the object caused by shear wave is perpendicular to the forward direction of the wave. P is faster than S wave, so it reaches the ground first, forming the first wave of seismic wave. According to the vibration direction of the initial wave, the source direction can be known. However, the initial wave is very weak, because it can only travel directly from the source to the ground receiving the seismic wave, and the energy carried by this part of P wave only accounts for a small part of the total energy of the seismic wave. If the seismograph is sensitive enough to respond to the first wave of the "first whistle", there will be many other vibrations unrelated to the earthquake, such as stamping your feet near it, which will cause it to react, thus making people mistake many vibrations that are not earthquakes for earthquakes. However, if the seismograph is to be kept "slow", it may not be able to "feel" the first wave of the earthquake, and it will not be "awakened" until the subsequent waves come one after another, but the vibration direction of these later waves cannot represent the direction of the source at all. In addition, recording an earthquake must have three elements: occurrence time, epicenter location and magnitude (earthquake intensity). Seismographs can only record the direction of the epicenter. It is also possible to measure the location of the epicenter by "networking" several seismographs; But it can't record the time of the earthquake, so it can't be "the first seismograph in the world".
"Hou Feng Seismograph"
Textual research on principle
According to scholars' research, Zhang Heng had used the inertia principle in mechanics at that time, and the "single column" actually played the role of inertia pendulum. At the same time, Zhang Heng must know something about the propagation and directionality of seismic waves, and these achievements were very remarkable at that time. But it was not until Europe 1880 that a similar instrument was manufactured, which was more than 700 years later than Zhang Heng's invention. There are two popular versions about the structure of the seismograph: Wang Zhenduo model (195 1 year), that is, the "single column" is a cylinder similar to an inverted wine bottle, and the mechanism of controlling the longkou is around the "single column". This model has been basically rejected recently. Feng Rui (2005) of Seismological Bureau put forward another model, that is, the "single column" is a pendulum with a small ball under it, which is located at the intersection of the "m"-shaped slideways (that is, the "Guan" mentioned in the Book of the Later Han Dynasty). During the earthquake, the "single column" poked the ball, and the ball hit the mechanism to control the opening of the longkou. In addition, Feng Rui's model also changed the toad from facing the bottle to facing the bottle, serving as the foot of the musical instrument. The model is simulated and tested, and the results are consistent with the historical records. So, what is the internal structure of the seismograph like? Many scholars have discussed this. As early as the Northern and Southern Dynasties, Xindufang in the Northern Qi Dynasty wrote Qi Zhun, and Gong Lin in the early Sui Dynasty wrote Jing of Shock Bronzes, all of which were described, with their schemata and production methods. Unfortunately, after the Tang Dynasty, both books were lost. Wang Zhenduo's theory has the greatest influence on the study of modern people. According to previous speculation, Wang Zhenduo discussed various possible structures inside the seismograph, and finally came to the conclusion that the working principle of the single column is similar to that of the inverted pendulum in modern seismographs. Specifically, the stigma is a copper column hanging upside down in the center of the piano body, and eight roads are erected around the stigma. The column stands upright with a high center of gravity. When there is a ground motion, it loses its balance and falls in one of the eight roads. There is a lever in the eighth lane, which is called the tooth machine. The lever passes through the appliance body and is connected with the upper jaw of the faucet. After the column inclines into the tunnel, the lever is pushed to lift the upper jaw of the faucet and spit out the copper pill, which plays an alarm role. The seismograph is made of pure copper, with a circle of eight feet and a raised lid, which looks like a wine bottle. The surface is golden yellow, and eight golden dragons are cast on the upper part, lying in eight directions: east, west, south, north, northeast, southeast, northwest and southwest. The dragon lay with his head down, with a small copper ball in his mouth, opposite to the toad crouching on the ground with his mouth open. In the center of the cavity of the seismograph, stands a copper column, which is thick at the top and thin at the bottom. There are eight cross bars around the copper column, which are called "eight lanes", and each cross bar is connected with a faucet. The copper column is an oscillating device, and eight channels are used to control and conduct the movement direction of the copper column. When the seismograph is impacted by seismic waves, the copper column will fall in the direction of the earthquake, pushing the crossbar and faucet in the same direction to open the longkou, and the copper ball will fall into the toad's mouth and make a noise to remind people of the time and direction of the earthquake. A bead is placed on the platform. If you press it gently, where will the beads roll? For another example, if we light a candle and put it on an uneven table, it will always fall to the lower side. Seismographs are designed according to these simple principles. Earthquakes can travel far away, but people can't feel them if they are too far away, but seismographs can detect them accurately. However, Chinese scientists believe that the working principle of the seismograph should be "pendulum principle", that is, the seismograph uses the inertia of the hanging column to detect earthquakes, rather than simply erecting an upright rod at the bottom of the instrument as mentioned in today's history textbooks.
Structural model:
Wang Zhenduo's inference has been widely endorsed. The model of Zhang Heng's seismograph displayed in China History Museum was restored according to the design of Wang Zhenduo. However, some scholars have put forward different opinions. Li Zhichao of China University of Science and Technology once objected to the inverted pendulum structure, and he put forward his own understanding of seismograph from a brand-new perspective (Li See Zhichao's The Ancient Meaning of Heaven and Man, Henan Education Press, 1995 edition). Li Zhichao believes that from the perspective of literature, the word Shi Ming in the Han Dynasty explains "column" and says "column, living also", which shows that the original meaning of the word column is an immovable support in architecture. Therefore, the inverted pendulum structure can not be called "column", but can only be called cone. "Du" means a set, which means that it is not an isolated pillar, but is equipped with eight sets of mechanisms, and the vertical cone can only be a polished rod. In this way, only from the name "single column", the theory of inverted pendulum can not be established. Li Zhichao further pointed out that the design of the inverted cone made all other parts mentioned in the original text redundant. Especially the huge bronze statue, which means nothing at all. In addition, from the point of view of physical evaluation, the performance of any measuring instrument can generally be characterized by two contradictory indicators: sensitivity and stability. The design of inverted cone just highlights the main contradiction of precision measurement technology. For example, in order to improve the sensitivity of seismograph, it is necessary to make the bottom of the inverted cone very small to form the cone tip, but the very small cone tip will bear huge gravity pressure and will gradually form irreversible deformation under the inevitable small vibration. The trend is that the supporting surface below the cone tip will form pits and the cone tip will become smooth. This process is irreversible and accelerating. In this way, the inverted cone will eventually fall down, whether there is an earthquake or not. If the cone tip is made so wide as not to deform in practice in order to improve stability, its sensitivity will be very low, and its perception will be greater than what people can detect, so the seismograph will lose its existence value.
Restoration research: mystery 1700 years ago, the seismograph disappeared in the war, and its appearance and working principle became an eternal mystery. In August, 2004, Henan Provincial Museum and China Seismological Network Center formed a research group to jointly study the new restoration model of Zhang Heng's seismograph. So far, this project has made great progress, and the research group has replaced the traditional "vertical rod principle" with "hanging pendulum principle". On April 16, 2005, this scientific research achievement was affirmed by experts in earthquake archaeology from China Academy of Sciences, National Museum and China Seismological Bureau. Experts believe that this restored seismograph restores the conceptual model to a scientific instrument for the first time, making it truly have the function of earthquake detection.
Acceptance: the seismograph repairs the model and repairs the conceptual model into a scientific instrument. On the morning of April 16, the acceptance committee composed of experts from seismology, archaeology, mechanical engineering and other related disciplines began to critically examine the seismograph restoration model (1/3 sample). In the afternoon, after intense discussion, seven experts from the acceptance team finally came to the conclusion that the new model reduced the conceptual model to a scientific instrument with earthquake detection function for the first time, and took a historic step in restoration research. This acceptance opinion means that the newly repaired seismograph has passed the acceptance of the phased results, and the follow-up work only needs to further optimize some technical details and make a final determination on the appearance. Tian Kai, vice president of Henan Museum, was deeply touched by this: "We are not only restoring a musical instrument, but also looking for the scientific spirit of the great scientist who was" not realistic enough "more than 0/000 years ago ..."
Wish: We must make the seismograph model "move". From 65438 to 0998, during the construction of the new Henan Museum, Tian Kai was in charge of the exhibition "Light of Ancient Henan Culture". Zhang Heng's seismograph needs to be exhibited in the Han Dynasty exhibition hall. At that time, the most authoritative model was displayed in the former Museum of Chinese History, which was designed by Mr. Wang Zhenduo 195 1. This egg-shaped model containing eight dragons became the "standard image" of the seismograph. Henan Museum asked Suzhou Astronomical Instrument Research Institute to copy a wooden model according to Wang Zhenduo's model and asked, "Can you make the seismograph move?" The answer is: no, even the one displayed in the Chinese History Museum can't detect earthquakes. But the other party can artificially install a device under the model to make it move. "We are exhibiting scientific instruments instead of toys, which is a deception to the audience. So at that time, I could only build a fixed model, but this complex remained in my heart for many years. " Tian Kai said. Six years later, I learned that researchers from the State Seismological Bureau and the National Museum were carrying out restoration work. In August 2004, Henan Museum signed a cooperation agreement with China Seismological Network Center to form a project team to jointly repair Zhang Heng's seismograph.
Solve the puzzle: Find the "suspension principle". The person in charge of this project is Feng Rui, a researcher from China Seismological Network Center. Teacher Feng said that how the seismograph worked more than 700 years ago is a mystery that must be solved first. In-depth study confirmed that the seismograph should be the pendulum principle, not the vertical rod principle of Wang Zhenduo's model. For decades, the negative opinions of seismological circles at home and abroad on Wang Zhenduo's model have never stopped. More modern western scholars believe that Zhang Heng's seismograph was lost because it did not meet the requirements of science and was not a scientific thing. Feng Rui said: "Only after seeing these severe criticisms did we feel the seriousness of the problem." After 1 years, the research group finally confirmed that the working principle of seismograph should be "pendulum principle" rather than "vertical rod principle".
Evaluation: This is a great leap forward. The most famous historical data of seismograph is recorded in the book Zhang Hengchuan in the later Han Dynasty, although it is only 196. Early recovery work is carried out on this basis. Feng Rui's research group expanded the textual research and utilization of materials to ancient documents such as Continued Han History and Post Han Ji, but the total number of words in related documents was only 23 1. These materials make the historical basis of its restoration more sufficient. In the development process, Feng Rui also adopted some new technologies and methods, that is, using the modern Longxi earthquake records received by Luoyang Seismic Station to calculate and simulate the wave effect of Longxi historical earthquake, then inputting the data into the computer, and then controlling the special shaking table to complete the reproduction of Luoyang ground vibration process, and using this motion signal to test and improve the restoration model on the shaking table. Experts in the inspection team believe that the new model has achieved good seismic response to four actual earthquake events and has taken a key step from conceptual model to scientific instrument. The research work has broken through the traditional mode of repairing ancient scientific instruments, which is a great leap. After the acceptance meeting, Academician Teng Jiwen of the Institute of Geology and Geophysics of the Chinese Academy of Sciences said: "The seismograph is a precious cultural heritage left by Chinese civilization, and scientists all over the world are trying to repair it. If we don't do this well, it will be a sin. In terms of principle and production technology, this restoration model conforms to the basic ideas of Historical Records and Zhang Heng ... This seismograph restoration model represents the understanding of modern people and is the best at this stage. "
Other news
On August 5, 2008, entrusted by the national research group of "Scientific Restoration of Zhang Heng Seismograph", Yuda Group of Yuda Bronze Culture Industrial Park in Xiaxian County, Shanxi Province successfully cast "Zhang Heng Seismograph". Its modeling design was completed by Professor Wang Peibo from the Sculpture Department of Tsinghua University Academy of Fine Arts. This new model is carefully cast with high-quality bronze and will be exhibited in the newly-built China Science and Technology Museum.
It is reported that the national research group of "Scientific Restoration of Zhang Heng Seismograph" is composed of experts from China Seismological Network Center, Tsinghua University Academy of Fine Arts, National Museum, Beijing Institute of Mechanical Industry Automation, Henan Museum and other units. Feng Rui, a researcher and seismologist at China Seismological Network Center, is the head of the research group.
Be questioned
Brief introduction of events
Some netizens posted on Weibo that Zhang Heng's seismograph, which is widely known in history textbooks, is actually a restored model from the 1950s, but what the seismograph was like 1800 years ago has long been unknown. Fang, a popular science writer, wrote that the seismograph built by Zhang Heng in those days was "probably just the same decoration as those models restored by modern people". Feng Rui, a researcher at China Seismological Network Center, said that the seismograph model successfully restored in 2005 can indeed monitor earthquakes.
Event origin
2010165438+2810.28, a netizen Yan Tao posted on Weibo, saying, "It was only yesterday that I learned that the national treasure Zhang Heng seismograph was made in the 1950s, and it was written by Wang Zhenduo (an archaeologist) according to the word 196 in ancient books. Because of the selection of teaching materials, Chinese people think it belongs to the Eastern Han Dynasty. In fact, the beads can't fall out. " Yan Tao may not have studied hard when he was a child. In fact, the textbook at that time clearly indicated in the illustration that it was a copy, and stated that the original had been lost. When this statement came out, it immediately triggered a hot discussion on the Internet. As of yesterday afternoon, this post has been forwarded 1.5 million times, with nearly 5,000 comments. Many netizens said that they didn't know before that the seismograph that frequently appeared in history textbooks and science and technology museums turned out to be just a "59-year-old" recovery model. They don't even know that this repair model can't work normally because of the wrong principle, which has been questioned and denied by Chinese and foreign scientists. In fact, the seismograph of waiting for the wind recorded in the Book of the Later Han Dynasty has long been lost. Some netizens said that this fact greatly hit people's confidence, and some even questioned other ancient scientific and technological achievements in China, such as the "Four Great Inventions". Teacher Han, who teaches history in a junior high school in Beijing, said that the current middle school history textbooks still use pictures of the seismograph model restored by Wang Zhenduo. They generally don't deliberately explain to students whether this is the original model or the restored model. "Even Zhang Heng's own portrait is simulated by later generations." Teacher Han said that when introducing the seismograph, they would only tell the students that "there is an organ in it, which can be felt during the earthquake and the beads will fall."
The seismograph model was restored at 195 1 year.
Fang questioned
The waves on the internet are sluggish, and the popular science writer Fang is angry in the media. He wrote in 20 10 12 1 questioning whether Zhang Heng's seismograph works. "The seismograph has long been lost, and whether it has the function of monitoring earthquakes has become a mystery." Fang said that many experts at home and abroad tried to restore the seismograph according to the simple description, but none of these restoration models can really be used to monitor earthquakes, but only "works of art" Fang said that in 2005, experts from the Seismological Bureau of China announced that after three years' research, they had established a new seismograph recovery model and realized the earthquake detection function for the first time. They claimed that the new seismograph model tested three real earthquakes in Tangshan, Hebei, Luxi, Yunnan and Mengyi, Vietnam. However, these three earthquakes occurred in 1976, 2000 and 200 1 year respectively, and the new seismograph model was only built in 2005. How to take the exam? Fang said that after understanding, the original new seismograph recovery model did not test the real earthquake, but simulated the real earthquake in the laboratory. Fang said that after the completion of the new seismograph restoration model, there will be many earthquakes of magnitude 5 or above in China every year, but within the monitoring range of the seismograph restoration model, it has never been heard that the restoration model has been monitored even once. The Wenchuan earthquake in 2008 was felt in Beijing. I didn't know that the restoration model exhibited in Beijing was detected. The party also questioned the authenticity of the seismograph recorded in Zhang Hengchuan of the Later Han Dynasty in predicting the Longxi earthquake, saying that some historical materials were contradictory and suspected that the earthquake was "a story fabricated to illustrate the magic of the seismograph".
195 1 year recovery model
Expert response
Feng Rui, a researcher at China Seismological Network Center who participated in the restoration of the 2005 seismograph model, said yesterday that the new seismograph restoration model is responsive to earthquakes, which has been identified by many academicians and experts. "Fang Zhouzi doesn't understand the earthquake field," Feng Rui said. They controlled a special shaking table based on the wavelength of seismic waves recorded in real earthquakes and completed the test of the seismograph recovery model. This is a "repeat" of the earthquake, not a simple "simulation". Feng Rui said that in order to monitor the real earthquake, we must first build supporting facilities such as foundations, and then put the seismograph recovery model on them. However, the cost of such monitoring experiments is very high, and problems such as site selection are not easy to solve. "We are working hard in this direction." Regarding the Longxi earthquake questioned by Fang, Feng Rui said that according to historical records, the earthquake occurred in A.D. 134. Feng Rui emphasized that these historical materials have been reviewed by professional historical seismologists. Due to the long history, some historical materials are inevitably biased, but the conclusion is that there was no problem that there was an earthquake in Longxi that year.
Textual research on nouns
In the Book of the Later Han Dynasty, it is recorded that "the diameter of the staff is eight feet". "Eight feet in diameter" has different interpretations. For a time, the mainstream explained: "Member is a common word. The diameter of the ruler is actually a circular diameter. It is the diameter of this circle today. " Although this explanation is quite popular, people no longer think that the seismograph is a giant after the archaeological discovery that the foundation of the house where the seismograph is placed is only nine feet wide.
The original meaning of the word "member" is left and right. The diameter of the staff means a circle. This is the meaning of the word "vast territory" that is often used now. In this way, a seismograph with a diameter of eight feet is actually about eight feet. Might overlap, Yi Long. It seems that these eight feet are not flexible. It really doesn't make sense if only this eight-digit number has nothing to do with the Eight Dragons and the rest are related to the Eight Dragons. Eight feet is the recorded value, and that ruler is the ruler used at that time. At that time, about one foot was equivalent to a little more than 23 centimeters made of silicon today. So today 8 feet is about 59 centimeters. This is an accurate radix. The following is the original content. It was actually a mistake.
"The diameter of the circle is eight feet", and "the diameter of the circle" is the circumference of the circle, not the radius of the circle. The circumference of a circle is eight feet, which is equivalent to 185 cm, and the diameter is 60 cm. Such a large instrument is reasonable. 1. China's earliest mathematical work "Calculation of the Perimeter" (written in BC 1 century) recorded that pi was "the diameter of three weeks in one week". Liu Hui, a mathematician in the Three Kingdoms period, thought that "the ancient number is nine, the pi is three, and its technique is sparse." And pi is calculated to be 3. 14 16, which is thousands of years ahead of the world. It can be seen that the terminology of each part of the circle is different from that of the Han Dynasty. At that time, the circumference of a circle was called "circle diameter" and the radius of a circle was called "circle". 2. Generally, the equipment should be prepared first, and then a special storage room should be built according to the size of the equipment. 1975, Henan archaeological team excavated a building on a hillside in the southern suburbs of Luoyang. This is the famous Lingtai built in the first year of Jianwu in the Eastern Han Dynasty. Lingtai is a high-rise building used by ancient emperors to observe astronomical phenomena and predict good and bad luck. According to data research, the "Zhang Heng Seismograph" was placed here and earthquake observation was carried out. This building is only 2.2 square meters. If the radius of the seismograph is eight feet (1.85 meters), there is no room for movement when it is put in. Obviously, it is not suitable. It should be built on a bigger one. If the diameter is 60 cm, it only accounts for one ninth of the total area of the ground, and there is still a lot of room for some supporting facilities, such as time leakage; 3. Any electrical appliance is user-oriented, which is conducive to production and operation on the premise of completing its functions. The smaller the volume, the better, not the bigger the better. The diameter of seismograph is not necessarily 1.85 m, but 60 cm, which is convenient for making, carrying, placing, operating and observing.
"All columns in the middle" means all columns in the middle. "Living alone" is a special term. At that time, an acrobatic called solo dance was introduced from the west. When describing the lively scene of Xijing in Zhang Heng's Ode to Xijing, Dulu looked for the lost land. It is this kind of acrobatics, in which Seek is climbing and Lost is a pillar, on which the actors climb and perform thrilling actions. The columns used by actors are called "single columns". There are two types of capital columns, one is fixed at the top and the other is fixed at the top and free at the bottom, which is difficult to implement. And this project is called "pole climbing". Dulu is a transliteration, while Duzhu is a local name. Just like "tank" is transliterated in a foreign language, its various components (tracks, turrets, etc. ) Use your own name. To measure ground motion, there must be a relatively stationary object, and the pressure between the moving object and the stationary object drives the instrument to move. When designing the seismograph, Zhang Heng must have started looking for the target from here. He was inspired by the performance of drew, or he did further experiments. When the surrounding columns are shaken, the hanging columns are relatively motionless. Therefore, use the principle of all columns.
Single bamboo,
The main part of seismograph is the stigma. Its structure is unknown. From the outside, it should be a pillar. There is no doubt about it. The key is how to wait for the wind on that pillar. How does it tell to turn off the engine when the wind blows? Is it naive to think of it as just a thick pillar? One interpretation of the word "capital" is that "the palace of the son of heaven is called the capital." It can be understood as "the head of the supervisor is called the place of the capital". If the director of the seismograph is Jun, can it still be called Du when it lives in that place? If the palace is in the shape of a pillar. There should be no problem calling it "Duzhu". There is nothing wrong with the explanation that all columns are "big columns, thick columns". Columns do look tall and thick (relatively speaking). It's like you see a water tower or a big chimney somewhere collecting dust. You won't object to the power equipment of water tower to lift water, and you won't object to the purification equipment of chimney dust removal and harmful gas reduction. So you won't object to the weather waiting equipment in the capital column. I also see that the palace of "Du Yue Palace" is a common term. Therefore, it can be seen that the capital column is by no means an impregnable hanging column. Capitalized columns are centered because there are capitalized columns in the middle. So it is inferred that there must be a waiting device inside.
All, big also. The emperor's palace is called the capital.
A column, an upright wooden column. By extension, anything that stands upright is called a column. Such as the mountain in the river and the bottom pillar. The stone pillar of Zheng is called Zheng Zhu.
The general term for the group rooms in palaces and city walls. The ancient name was Gong.
Medium, impartial is called medium. The mouth is like a square with a vertical boundary. The epicenter was in the center of the square.
Two key technologies
1, "When the earth moves, it respects the vibration, and then it looks like it, and the dragon machine makes the shot, that is, spits pills." This technique is the key to predict P-wave earthquakes. It is completed by the structure of "machine and customs control". draw
The P-wave earthquake made the statue move in the same direction, the closed end moved after contacting the top pillar (relatively motionless), the upper end of the connecting rod moved in the opposite direction to start the machine, and the copper ball was opened by the dragon mouth and dropped. Complete the earthquake report.
2. "Although Yi Long rises, the other seven songs will not move". This technology is the key to the positioning function. It is completed by the special structure of "there is a column in the respect and eight roads beside it". draw
When the first copper bullet falls, then the top pillar falls away from the capital pillar, and then the other seven levels are not affected by the capital pillar, "seven don't move."
There are two of them.
Combined atlas
The story of the seismograph, which most people in China are familiar with, is actually not too long ago-it was not until AD 1950 that the seismograph in this story was "made" and entered the textbooks. It was not until decades later that it was rediscovered and "made".
Generations of China students have heard this vivid story from their teachers: Zhang Heng, a scientist in the Eastern Han Dynasty, invented the seismograph. This seismograph is like a wine bottle with a slender vertical rod in the middle. During an earthquake, this straight pole will fall in the direction of the earthquake. When the faucet in that direction is shot down, the Longkou will open and spit out a copper pill, which just falls below.