Chapter 12 Chapter Nine Science and Technology Synthesis - "Mo Jing", "Mengxi Bi Tan"
As we all know, in ancient times, natural science and technology were closely integrated with religious theology and had no independent position.At that time, "Shi" who managed clerical affairs and "Witch", "Zhu" and "Bu" who were in charge of religious affairs were the possessors of knowledge, including of course scientific and technological knowledge.For example, the oracle bone texts of the Shang Dynasty are the records left by the divination of the Shang nobles, but we can learn from them the level of science and technology at that time.When people gradually get rid of the shackles of religious theology and begin to re-understand the natural world and man himself, although scientific and technological knowledge plays an important role in the process of transformation, it still has no independent position.In the West, science and technology are part of natural philosophy, but in my country, because more attention is paid to the study of social ethics and ruling ideas, science and technology are mostly found in related theories.This has a profound influence in ancient China.Its performance is: even after the appearance of scientific and technological monographs, a large amount of scientific and technological knowledge in our country is still preserved in classics, history, philosophy and other documents.For example, there are very few works on technology in ancient my country, and the earliest records of technological achievements that have had a major impact on the development of the world, such as the Four Great Inventions, are found in other historical documents.In ancient Chinese cultural classics, there are many works in which scientific and technological content accounts for a large proportion, and they are often mixed together regardless of disciplines.These works should also be counted among the scientific and technological works.In addition, the content and theories of some works have had a huge impact on the development of science and technology, and we should also understand them.
And "Shangshu" is one of the earliest documents in our country, and there are many scientific and technological contents in it.It is the earliest collection of poems in my country, including folk songs from the Western Zhou Dynasty to the Spring and Autumn Period and some movements of Shang and Zhou temples.Many of these poems contain records and descriptions of agricultural knowledge, names of animals and plants, astronomical phenomena, and geoscience knowledge.For example, "both Pu and long, and the scenery is the hill, look at its yin and yang, and watch its flowing spring" ("Daya Gongliu"), which refers to choosing land with sufficient sunshine and good water conservancy conditions for cultivation; "May katydid Moving stocks, Shaji vibrating feathers in June..." ("Bin Feng·July") describes the phenology; ") is the world's earliest record of a solar eclipse; and so on.These contents reflect the level of scientific and technological knowledge at all levels of society at that time. "Shangshu" is a compilation of ancient history books. Among them, the geography special chapter "Yugong" has been introduced before. In addition, "Luogao" records that Zhou Gong chose to build a city site in Luoyi and drew a map. It is the earliest record in the handed down documents of our country. map; "Yao Dian" also has records of observing Sizhong Xing.In particular, "Hong Fan" first proposed the Five Elements thought, which had a great influence on the development of science and technology in ancient my country.
During the Spring and Autumn Period and the Warring States Period, society changed, schools of thought rose, and cultures gathered.There are a lot of scientific and technological content in the works of scholars.For example, "Xunzi" puts forward the idea of rational protection and utilization of animal and plant resources; in "Xunzi", it discusses the origin of the universe, limited and infinite time, variable species, and biological chains, and questions the theory of Gaitian; "Zizi" He defined the universe as "the upper and lower sides are called the universe, the past and the present are called the universe", and the idea of the earth's rotation has sprouted. "Guanzi" has made even greater achievements in science and technology. It puts forward the idea of "water is the origin of all things", and also puts forward the idea of "essence and energy" transforming all things, and in the chapter "Earth Members" Ecology and soils are thoroughly studied.Among the hundreds of schools of thought, Mohism has the most in-depth research in the field of science and technology, and has achieved the highest achievements. "Mo Jing" is a theoretical classic of the Mohist disciples, in which the natural science knowledge is rigorously discussed and the arguments are accurate. Some basic concepts and principles are put forward in mathematics, optics, mechanics and other aspects. It is an excellent scientific and technological work.In addition to the writings of the philosophers, there are also many scientific and technological contents in other documents at that time. "Yi Zhuan" is the oldest commentary. In "Xi Ci", the theory of "Tai Chi" transforming all things in the world is put forward, pointing out that all things are in the process of changing with each passing day, and the changes are summarized as the two things of yin and yang. The relationship between the unity of opposites; this article also summarizes the inventions and creations of the ancients, and puts forward the scientific view of "observation and creation", that is, to observe natural phenomena and simulate creation. The scientific thought of "Yi Zhuan" had a great influence on the development of science and technology in later generations. "Zhou Li" is a Confucian classic, which brings together the political system from the Western Zhou Dynasty to the Warring States Period. It has a complete and systematic scientific and technological management system, including the appointment of officials, responsibilities, the number of subordinates, and related policies and decrees.Since then, related systems and policies in successive dynasties have been developed on this basis.In addition, in this book, it records scientific and technological knowledge in astronomy, calendar, meteorology, geography, agriculture, medicine, biology, food, metallurgy, textiles, etc. Most of the phenomena are clouds or halos around the sun. "Lu's Spring and Autumn" is a collection of various theories compiled by Lu Buwei's disciples. In addition to the four agricultural papers mentioned above, the highlight is that it starts with the twelfth century and describes the monthly phenology and matters that should be operated. The predecessor of Yueling in later generations.At the end of the Warring States Period, there was also the earliest exegetical work in my country——"Er Ya". Among them, the five chapters Shi Chong, Shi Yu, Shi Bird, Shi Beast, and Shi Animal reflected the animal classification system in the pre-Qin period, which is very close to modern animals. The classification of science; Shicao and Shishu are subdivided into subcategories, and similar plants are arranged together, and their classification ideas have reached a very high level; Shidi, Shishan, Shiqiu, and Shishui reflect the topographical classification knowledge Also very rich.Many people in successive dynasties commented on "Erya", which promoted the development of ancient scientific and technological knowledge, especially natural history.
From the Qin and Han Dynasties to the Sui and Tang Dynasties, my country's ancient science and technology continued to enrich and develop, and the comprehensive scientific and technological literature also reflects this feature. "Huainanzi" was compiled by Liu An, king of Huainan in the Western Han Dynasty, and his disciples. In "Tianwenxun", the author used the theory of Qiqi, Yinyang, and five elements to describe the complete process of the creation of the universe. There is a similar description in "Spiritual Training". It can be said to be the most systematic theory of universe creation in ancient China; "Tianwen Xun" records the method of observing the humidity of suspended soil charcoal and the average degree of the moon's daily movement, which is a new achievement of the development of science and technology in the Qin and Han Dynasties. "Taixuan Jing" is an imitation of "Zhouyi" written by Yang Xiong in the Han Dynasty. On the basis of the calendar and astronomy at that time, he constructed an all-encompassing cosmic system. (1), yang (one) binary system develops into odd (one), even (one), and (one) ternary system, and its arrangement mode is a ternary number sequence from a mathematical point of view."Lunheng" written by Wang Chong of the Eastern Han Dynasty is an important work in the history of science. In the book, he used scientific knowledge as a weapon to criticize the theory of "interaction between heaven and man" and the superstition of prophecy. It is formed by the gas phase, and the relationship between the tide and the moon's profit and loss is analyzed, and so on.The scientific knowledge involved in the book includes astronomy, physics, biology, medicine, metallurgy and other fields, reflecting the new level of scientific development at that time.Cui Bao's "Annotations to the Ancient and Modern Times" is an early work on ancient and modern famous things. It records a lot of scientific and technological knowledge about vehicles, clothing, cities, music, birds, beasts, fish and insects, vegetation, etc. , Yangsui (concave mirror) making materials are all recorded in this book for the first time.During the Han, Wei and Six Dynasties, the notebook novel style works rose, which is of great significance to the records of scientific and technological inventions and creations as well as scientific and technological knowledge.For example, "Xijing Miscellaneous Notes" written by Ge Hong in the Jin Dynasty recorded how the craftsman Ding Huan and others invented the "changman lamp" and "quilt incense burner". It is an important historical material of history and botany history; "Youyang Zazu" by Duan Chengshi in the Tang Dynasty recorded a large number of medicines and famous doctors, as well as knowledge about rare birds and animals, vegetation, insects and fish, among them, squid put ink to avoid enemies, snails The careful observation of animal behavior such as clam symbiosis is an important historical material for the history of biology.Beginning in the Tang Dynasty, the activity of compiling class books became popular, and many scientific and technological knowledge and documents were included in related categories, which played a role in preserving scientific and technological documents. For the scientific and technological content of the subject, for example, a large number of ancient documents about missing engravings are collected under the "Tianbu", among which there is the second-level missing engraving part of Zhang Heng's "Annotation of the Armillary Sphere". There are more than 500 volumes of geography books, the original books have long since disappeared, and its "Preface" is preserved in "Beginners", etc.After the Tang Dynasty, similar books appeared in almost all dynasties. The large ones included "Taiping Yulan" in the Song Dynasty and "Integrated Ancient and Modern Books" in the Qing Dynasty. Now when we study the history of science, we often go to these kinds of books to find precious materials.
The Song and Yuan Dynasties were the peak period of my country's scientific and technological development, which was also reflected in the comprehensive scientific and technological literature. The specific manifestation is that the scientific and technological content increased and had a research nature. "Relationships of Objects" and "Gewu Rough Talk" can be said to be works of natural history. Their common feature is that they have compiled a large amount of experience and knowledge in daily life, and most of them are based on personnel, weather, geography, grass, trees, Flowers, insects, clothes, medicines, etc. are classified, and some craft techniques are recorded in such books.In this period, there are more scientific and technological contents in the notebook-style works. For example, Su Shi’s "Dongpo Zhilin" contains about one-fifth of the entries about science and technology, involving medicine, geography, agriculture, water conservancy, wine making, food hygiene, astrology, and alchemy. Among them, the excavation method and salt production process of Zhuotong well in Sichuan are the earliest and most detailed records.Among the notebook-style works, Shen Kuo's "Mengxi Bi Tan" is a great scientific and technological work. There are more than 600 articles in the book, of which nearly 200 are about science and technology, and the subjects involved are also very wide. The world is in a leading position.The Song Dynasty also developed scientific thinking. Among them, Zhu Xi's "searching things to gain knowledge" in "Zhu Zi Yu Lei" inherited the fine tradition of traditional Confucianism.In the Ming Dynasty, this idea developed into a scientific view of gaining true knowledge through personal practice, which had a profound impact on the development of science and technology.
After the middle of the Ming Dynasty, with the budding of capitalism, some intellectuals began to turn to pragmatic learning.At the end of Ming Dynasty, Huang Daozhou developed Zhu Xi's "Ge Wu Qiong Li" in "Rong Tan Wen Ye", and his "Ge Wu Qiong Li" had an obvious scientific research tendency.A typical example influenced by this kind of "Ge Zhi" thought is "Xin Xin Ge Gu Yao Lun" written by Cao Zhao in the Ming Dynasty. However, he emphasized in his preface that he wrote it on the basis of real objects and verified the literature, and the gold and silver detection methods recorded in it were conclusive literature.In the development of science in this period, Fang Yizhi was an important figure.Fang Yizhi is one of the early enlightenment thinkers in my country. In his "Tong Ya" and "Little Knowledge of Physics", on the one hand, he made a comprehensive record of ancient Chinese scientific knowledge, and on the other hand, he absorbed some western scientific knowledge at that time. Knowledge.Since he is a scientist as well as a philosopher, the book runs through materialist philosophy and natural science thoughts, and has made great achievements.
After entering the Qing Dynasty, the dissemination of western scientific knowledge became more and more widespread. Many comprehensive scientific works absorbed western scientific and technological knowledge, and most of them focused on the comparative study of Chinese and Western science. The research of traditional science declined day by day.
"Mo Jing" is the scientific, logical and philosophical works of Mohists in the pre-Qin period.Mohism is an important school among the hundreds of philosophers that emerged in the Spring and Autumn and Warring States Periods. Together with Confucianism, it is called "Xianxue".The founder of the Mohist school was Mo Di (didi). According to legend, he was originally from the State of Song, and later lived in the State of Lu for a long time.He is a famous thinker and statesman in ancient my country, and also a natural scientist with outstanding contributions.Mozi, the summary of the works of the Mohist school, is the recounting of the words and deeds of Mo Di by the disciples of the Mohist school. There are 71 original books in "Mozi", of which 53 are extant. Among them, "Jing Shang", "Jing Xia", "Jing Shuo Shang" and "Jing Shuo Xia" constitute the "Mo Jing".Some people think that the "Mojing" should also include two chapters, "Da Qu" and "Xiao Qu".
"Mo Jing" is the main part of "Mozi". It is said that all the disciples of the Mohist school recited it at that time, and it became the theoretical classic of the Mohist school.The book is rich in content and rigorous in structure, involving epistemology, logic, economics, natural science and other fields.There are about 180 articles in the book, including about 50 articles related to natural science.Its style is: "Jing" is a defining article, "Shuo" is a text explaining "Jing". The first character or the first and second characters of each article in "Shuo" is the standard word, which is the same as the first word or the second and third characters of the same article of "Jing". search.
The reason why there are many natural science entries in Mohism is closely related to the social status and thinking methods of Mohist scholars.First of all, the Mohists' social propositions are "universal love", "non-aggression", "frugal use" and "frugal burial", which represent the interests of small handicraft producers.Mozi himself was a craftsman, and most of his disciples were skilled craftsmen from the lower classes of society, so it was natural for him to accumulate and summarize natural science knowledge in his daily labor practice.Secondly, the Mohists attach great importance to the application of natural scientific knowledge in social production and social life, and believe that scientific knowledge is an important weapon to realize their own ideas and benefit the public, that is, "good for the people is called a coincidence, and not good for the people is called clumsy."Third, the Mohists have mastered relatively correct epistemology and methodology.They divide the sources of knowledge into "hearing knowledge", "explaining knowledge" and "knowledge", and believe that "knowledge" obtained in practice is the most reliable.At the same time, they also pay attention to the abstract comparison and synthesis of perceptual knowledge obtained in practice to form rational knowledge.At this point, Mohism's rich knowledge of logic provides an extremely important tool for solving problems.
"Mojing" has the most outstanding achievements in physics and mathematics.
The exploration of the natural world in which human beings thrive is an important aspect of the academic contention of the pre-Qin philosophers.In this respect, Mohism is unique, establishing a view of nature and cosmology.In the view of Mohists, the natural world is a unified whole, the individual and the part are separated from the whole, and are a part of the unity.Parts do not exist in isolation, but are closely related to the whole.This idea is used in Mojing's wonderful discussion of time and space. "Mo Jing" says: "For a long time, it will make up the difference", "Yu, it will make up the difference". "Jiu" means time, "Yu" means space, and "Mi" means to fill, cover, and contain.Time includes the past and the present, and it is endless; space is vast and boundless no matter where you look at it, from top to bottom.This is the definition of time and space given by the "Mojing", which already includes the idea of infinite time and space.However, the concept of time is reflected in the order of things in the process of change, and the concept of space is formed from the movement of objects in the process of movement, so "different times" and "different places" are actually a limited concept. of time and space. The "Mojing" uses a word "Mi" to express the overall concept formed by the close connection of various parts of time and space.Later, the "Mojing" used "finitude" and "infinity" to specifically discuss the relationship between the finite and infinite of time and space. The "Mojing" also believes that time and space are closely related, and links them with the movement of objects for illustration.It believes that the movement of an object must pass through a certain time and space; it must take a certain time to travel through a certain space; the object is at a specific position at any time;More than 2,000 years ago, the Mohist school could have such a scientific thought about the mechanism of time and space, which is really amazing.
Modern physics tells us that during various changes in nature, matter can neither be destroyed nor created, and its total amount is constant, which is called the principle of matter conservation.This idea already exists in the "Mo Jing".It points out that what already exists cannot be eliminated, and the loss of a part of an object is a "loss" to the object, but the total amount of the entire object does not decrease.The book "Guan Zi" at about the same time also said: "The world cannot be destroyed", which means that the total amount of all things in the universe cannot be destroyed.This shows that in ancient my country, the idea of material immortality existed very early.
The knowledge of mechanics in Mo Jing is the richest and most concentrated in the pre-Qin works.For the movement of objects, the book gives a strict definition, "movement, or (field) migration".That is to say, motion is the movement of the object's position, from one place to another.This is consistent with the current definition of mechanical motion. "Mojing" believes that stillness is an object in the same position in space within a certain time limit.The book also further discusses the dialectical relationship between movement and stillness, thinking that like archery, it is very obvious to advance a large distance in a very short time; There is a short period of stillness, but as far as the whole process of crossing the bridge is concerned, the stillness is only temporary and relative. Through the relative stillness of each step, the entire movement of crossing the bridge is completed.This thinking method of putting stillness into motion is very profound.
The definition of force in Mojing is derived from the concept of human physical strength. "Mojing" calls the human body "sentence", that is, "shape", and the process of changing the movement of the human body through lifting, holding, throwing, hitting, etc. is called "fen". In this way, it defines force as "the reason for punishment". Fen also".That is to say, force is the reason why people make movement shift and change.When explaining this definition, the book clearly points out that force and weight are equal, and lifting heavy objects is a kind of "strength". Before the 16th century, European scholars believed that force was the reason for maintaining the motion of objects. In comparison, the understanding of force in the "Mojing" is much more advanced.
The use of leverage and the use of weighing instruments were very common in the Spring and Autumn Period and Warring States Period. "Mojing" analyzed the principle of lever balance from a scientific point of view, pointing out that the balance of a lever not only depends on the weight added to both ends, but also has something to do with the length of "Ben" (heavy arm) and "Biao" (arm of force). With the concept of torque.Mohist scholars knew the relationship between distance and balance earlier than Archimedes, but it is a pity that they did not give a clear quantitative relationship.
The principle of buoyancy has been simply recognized in the "Mo Jing".It says that for a large object, the part that sinks in the water is very shallow, this is because the weight of the object is in balance with the buoyancy of the water.In addition, the book discusses simple machines such as pulleys and inclined planes, as well as tension and gravity.
"Mojing" also recorded a wealth of geometric optics knowledge.Mohist scholars conducted the world's earliest small hole imaging experiment, explaining the linear propagation of light.A small hole is made on the sunny wall of a dark hut, and a person stands outside facing the small hole, and an upside-down figure appears on the opposite wall in the room.Why does this strange phenomenon occur?The Mohists explained that light passing through a small hole is like shooting an arrow, and it goes in a straight line. The head of a person covers the light above, and the shadow is below; the feet of the person cover the light below, and the shadow is above. It became an inverted shadow.This was the first scientific explanation for the straight-line propagation of light.Using this property of light, the Mojing also explains the relationship between moving objects and shadows.The book says that the shadow of a moving object does not move, why does the shadow seem to be moving?That's because old shadows disappear and new shadows appear, which are constantly changing and changing positions.
The "Mojing" studies plane mirrors, concave mirrors and convex mirrors.For example, when discussing the different situations of concave mirror imaging, it is pointed out that when the object is placed inside the center of the sphere, the image obtained is upright, the image close to the center of the sphere is small, and the image far away from the center of the sphere is large; when the object is outside the center of the sphere When the object is at the center of the sphere, the image and the object coincide. The "Mojing" uses the center of the sphere to distinguish the relationship between the object and the image, and does not explain the image between the center of the concave mirror and the focal point. This is its shortcoming.But in the initial stage of optical knowledge, these scientific experiments of Mohism are of great significance.
In terms of mathematics, the "Mojing" puts forward a series of definitions of geometric concepts.For example, "圆 [huan ring, that is, a circle], one center has the same length." This is very consistent with the definition of a circle in modern mathematics, "the locus of points equidistant from the center point".Another example, "straight, coherent", refers to the definition of a straight line with three points on the same line; The "Mojing" also puts forward the concepts of "end", "ruler", "area" and "point", which are roughly equivalent to the point, line, surface and body of modern geometry. These mathematical contents in Mojing indicate that theoretical geometry had begun to germinate in our country during the Spring and Autumn Period and the Warring States Period.
"Mo Jing" is the product of the combination of production practice at that time and Mohism's unique scientific experiments and theoretical thinking. It is a very precious wealth in the history of science and technology in our country.However, it is a pity that the scientific tradition of Mohism has not been able to continue and has been obliterated by history.It was not until the Qing Dynasty that Zou Boqi and others discovered the scientific content in it that people paid more and more attention to it.
"Mengxi Bi Tan" written by Shen Kuo in the Northern Song Dynasty is a comprehensive academic work in the style of notes.Shen Kuo (AD 1031-1095) was born in Qiantang (now Hangzhou, Zhejiang).He liked learning and was good at thinking since he was a child. He read all the books at home when he was 14 years old.Shen Kuo once edited and proofread books in the Zhaowen Library of the capital, and also worked as a lecturer in Jixian College. The convenience of his position gave him the opportunity to read many royal collections and enrich his knowledge.He is versatile and has made remarkable achievements in repairing water conservancy, managing finances, fighting wars, writing poems, archeology, and conducting scientific research.After Wang Anshi's reform failed, Shen Kuo, who actively promoted the new law, was demoted many times. At the age of 58, he settled in Mengxi Garden in Runzhou (now Zhenjiang, Jiangsu Province) until his death.In his later years, Shen Kuo carefully summarized his life experience and scientific activities in Mengxi Garden, and devoted himself to writing. "Mengxi Bi Tan" was written by him during this period.
"Mengxi Bi Tan" has 30 volumes in total, including 26 volumes of "Bi Tan" (main edition), three volumes of "Bi Tan", and one volume of "Continued Bi Tan", divided into 17 categories: stories, identification, rhythm, image and number, personnel, Official administration, wit, arts and literature, calligraphy and painting, skills, utensils, miracles, strange things, fallacies, ridicule, magazines, and drug discussions, a total of 609 articles, including about 200 articles on natural science and technology, involving mathematics, physics, and chemistry , astronomy, geography, biology, agronomy, medicine and craft technology, there are not only records of past and current scientific and technological achievements, but also Shen Kuo's own research results.
Shen Kuo spoke highly of the practical experience and inventions of the working people, and believed that science and technology cannot all come from "sages."He recorded many folk scientific and technological figures and achievements in "Mengxi Bi Tan".For example, Bi Sheng, the "commoner" who invented movable type printing for the first time in the world, Wei Pu, a commoner almanac, Coincidentally, Longmen's superb hydraulic engineering, Yu Hao, a woodworker with superb craftsmanship, and his "The Wooden Classic", and so on.These are materials that have never been seen in official history books.
Shen Kuo once presided over the work of the Sitianjian, and has deep knowledge of astronomy and calendar.He attached great importance to the improvement of astronomical observation methods, and wrote three papers, "The Armillary Sphere Discussion", "Fulou Discussion" and "Jingbiao Discussion", which explained in detail the principle of reforming the instrument and his astronomical insights, which are important in the history of astronomy in our country. literature. This activity is recorded in "Mengxi Bi Tan", which can be compared with the records in "Song History · Tianwen Zhi".In "Mengxi Bi Tan", Shen Kuo gave a detailed description of the trajectory of the five stars and the scene of the meteorite falling, which is the result of his careful observation.He also proposed for the first time that the length of a day on the winter solstice is shorter than that on the summer solstice, which is of great significance in the history of astronomy.In the book, Shen Kuo advocated the use of the Twelve-Earth Calendar, which is closely related to agricultural production, in view of the shortcomings of the traditional yin-yang combined calendar in the calendar arrangement.This calendar is similar to today's solar calendar, simple and scientific.For more than 800 years, the British Met Office used the Shaw calendar, which is very similar to the twelve solar calendars, for agricultural climate statistics.
Shen Kuo also had in-depth research in mathematics. "Mengxi Bi Tan" recorded his two important achievements in the art of gap accumulation and the art of converging circles.Shen Kuo put forward the correct method to calculate their total number through the study of piles with gaps such as stacked wine jars and chess pieces.This is the "gap product technique", which is a method of summing high-order arithmetic series.This achievement is the first of its kind for Yang Hui in the Southern Song Dynasty and Zhu Shijie in the Yuan Dynasty. "Meeting the circle" is a problem of finding the arc length with the known circle diameter and sagittal height of the bow.Shen Kuo derived an approximate formula for finding the arc length of a bow.This formula was used in the "arc and sagittal cutting circle" in the "Shou Shi Li" by Wang Xun, Guo Shoujing and others in the Yuan Dynasty.
Shen Kuo's achievements in physics are manifold. "Mengxi Bi Tan" records that he has studied the four installation methods of the compass (placed in the water, on the edge of the bowl, on the nails, and hung by a thread) and compared their advantages and disadvantages. He believes that the hanging method is the most sensitive and accurate.He also found that the magnetic needle is "often slightly to the east, but not all to the south".This is the earliest record of geomagnetic declination in the world.The west discovered the geomagnetic declination only when Columbus sailed to America for the first time in 1492 AD, 400 years later than Shen Kuo.
Concave mirror, called "Yangsui" in ancient times, can make fire in sunlight.Shen Kuo discovered its focal point in the experiment of making fire with a concave mirror.In the imaging experiment of the concave mirror, he called the focal point "this" or "obstacle", and explained that when the object is within the focal point, a positive image is obtained, but there is no image at the focal point, and an inverted image is obtained when it is out of the focal point. This achievement recorded in "Mengxi Bi Tan" is a step ahead of the research in "Mojing".
The resonance phenomenon in acoustics was discovered in my country during the Warring States Period. "Mengxi Bi Tan" records the resonance experiment made by Shen Kuo.Cut a paper figurine and put it on the strings of the qin. If you flick the string that resonates, the paper figurine will jump and vibrate, but if you flick other strings, the paper figurine will not move.This experiment predates the same experiment done by Europeans by centuries.It was not until the 17th century that Noble and Pigott of Oxford used "paper game codes" (equivalent to paper figures) experiments to conduct resonance research.
"Mengxi Bi Tan" also records many outstanding conclusions of Shen Kuo in geology.When he visited the eastern part of Zhejiang Province, he inspected the geomorphological characteristics of Yandang Mountain's steep and steep peaks, high cliffs and deep valleys, and clearly pointed out that this was the result of water erosion.He also linked to the earth peaks in the deep gullies and huge gullies on the Northwest Plateau, explaining that their causes are the same.In the book, Shen Kuo deduced that this area was a seashore in ancient times based on the fact that there are many snail shells and oval gravels distributed in bands between the cliffs of Taihang Mountain. of.Correctly and scientifically explained the formation process of the North China Plain.
Shen Kuo also inferred the changes of ancient climate based on the observation of fossils. "Mengxi Bi Tan" records that the embankment of the Yellow River in Yanzhou (now Yan'an, Shaanxi) collapsed, and a piece of soil was exposed.Shen Kuo compared it with the fossils of peach pits, reed roots, fish, and crabs found in other areas, and believed that the fossil species in other areas were local animals and plants, and the climate here was not suitable for the growth of bamboo. Therefore, he judged that in ancient times this place must have been "low and humid" and suitable for the growth of bamboo.It was not until 1763 that someone in Europe put forward a similar view on the correct inference of paleoclimate changes based on fossils.
"Mengxi Bi Tan" also records Shen Kuo's investigation and research on oil and mineral resources in Northwest China.Shen Kuo personally collected oil and made oil smoke ink.Using petroleum to make ink is Shen Kuo's first initiative in utilizing petroleum.He also pointed out that the underground oil resources are very rich, and predicted that "this thing will become popular in the world in the future".In addition, the word "petroleum" was first used by Shen Kuo, which is simpler and more appropriate than "shiqi", "shizhi water", "kerosene" and "naphtha" in previous literature, and it is still used today.
In "Mengxi Bi Tan", Shen Kuo conducted in-depth research on the surveying and mapping of maps.He deleted the "Daoli" in Pei Xiu's six-body cartography (see Chapter Geography), and added "Pong-test" and "Mutual integration", that is, to emphasize the accuracy of the verification and stitching of maps after map drawing.He also improved the original map in all directions and subdivided it into 24 directions, which further improved the accuracy of the map.Later, 24 directions were marked on the compass used by people.Shen Kuo also once made a "wooden map" of the topography of the area close to the Liao Kingdom in the north - a topographic model map.This kind of three-dimensional map appeared more than 700 years earlier than Western Europe.
Shen Kuo's "Mengxi Bi Tan" is a treasure house of scientific and technological materials in the Song Dynasty, a masterpiece in the history of Chinese science and technology, and a precious heritage in the history of world science and technology. It is known as "the coordinate of the history of Chinese science and technology".
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