The history of the four great inventions?

Four Great Inventions is a viewpoint about the history of China's science and technology, which refers to the four great inventions in ancient China that had great influence on the world. They are important creations of working people of ancient Han nationality, generally referring to papermaking, compass, gunpowder and printing.

Papermaking:

About 3,500 years ago, in the Shang Dynasty, China had written characters carved on tortoise shells and animal bones, called Oracle Bone Inscriptions. In the Spring and Autumn Period, tortoise shells and animal bones were replaced by bamboo chips and sawdust, which were called bamboo slips and wooden slips. Oracle Bone Inscriptions and bamboo slips are very heavy. During the Warring States Period, Hui Shi, a thinker, liked reading. Every time he goes out to study, he is followed by five carts full of bamboo slips, so there is an allusion to learning to be rich and having five cars. In the Western Han Dynasty, among the court nobles, they wrote with silk or cotton paper. Silk is the general name of silk. Writing on silk is easy. It is not only much more than bamboo slips, but also can be painted on them, but it is expensive and can only be used by a few royal nobles.

People all know that Cai Lun makes paper. In fact, papermaking was invented in China before Cai Lun made paper on a large scale in the Eastern Han Dynasty. Many ancient pieces of paper from the Western Han Dynasty unearthed in China in the 20th century can prove this point. This is not to deny Cai Lun's contribution to papermaking, but to say that Cai Lun's papermaking is not a sudden invention, but a process of technology accumulation. Plant fiber paper unearthed in the Western Han Dynasty is the predecessor of Cai Lun papermaking. Cai Lun has expanded the range of raw materials for papermaking, and rags, fishing nets, bark and hemp heads can all be used for papermaking, among which bark papermaking is his invention. His papermaking process is more complicated. Papermaking found him, and he got rid of the status of textile vassal-all the by-products discarded after textile were used to make paper. Cai Lun developed papermaking into an independent process.

Compass:

"China's earliest compass theory is the" induction theory "based on the theory of Yin-Yang and Five Elements." According to Guan Zengjian, Shen Kuo, a great scientist in China in the middle of the1/kloc-0 century, is still puzzled by the compass. His "Meng Xi Notes" introduced the artificial magnetization method of the compass, the discovery of the magnetic declination angle and the erection method of the compass, but he didn't know why the compass was guided-"guided by a magnet" ... it couldn't be justified! Subsequently, scholars put forward various compass theories based on the theory of yin-yang and five elements and people's understanding of the shape of the earth at that time. For example, Guan's Geography refers to Mongolia, which was written in the Song Dynasty at the latest, first put forward the following logic:

"Magnetic needle is made of iron, and iron belongs to gold. According to the five elements, gold is born in water and the north belongs to water, so the water in the north is the son of gold. Iron comes from magnets, which are bred by the spirit of the sun, which belongs to fire and is located in the south, so the south is equivalent to the mother of magnetic needles. In this way, the magnetic needle should not only take care of the mother, but also miss the children, naturally pointing to the north-south direction. "

The compass principle of the Southern Song people still thinks that "the compass refers to the spirit where the sun is located" only revolves around the phenomenon of magnetic declination, and the argument is based on the coordinate system that turns to geographical orientation-the ancients in China thought that the ground was flat and limited in area, so there must be a center on the ground, and the meridian passing through the center is the only north-south direction. Zeng Sanyi, a member of the Southern Song Dynasty, believed that once the geodesy is not on this north-south line, the compass points to nature "less biased". In the Ming Dynasty, it was pointed out that the correct guiding direction was determined by the earth azimuth system, and the deviation angle was determined by the celestial azimuth division system. Guan Zengjian believes that this statement "embodies the embarrassment of traditional compass theory in the face of the contradiction between yin-yang induction theory and magnetic declination".

During the Wanli period of the Ming Dynasty (A.D. 1573 ~ 1620), missionaries came to China, bringing western compass theory, earth theory and related scientific and technological knowledge. Influenced by it, China scholars began to explore the compass theory from a new angle. In this process, the functions of Yin-Yang and Five Elements are gradually weakened, and the analysis from the mechanical point of view is increasing. However, the scientific theory put forward by Gilbert in 1600 is not unified in western academic circles, let alone in the East. Among the missionaries, ferdinand verbiest, a Belgian Jesuit who came to China in 1658, has the most systematic compass theory, but he thinks that the magnetic needle points to the geographical north and south poles of the earth itself, and his theory is still limited to the scope of ancient science, unlike Gilbert who realized that the earth itself has magnets. Ferdinand ferdinand verbiest's theory had a far-reaching influence in China. Until the middle of19th century, some scholars in China still used it to explain the compass problem. At this time, missionaries who came to China in the late Qing Dynasty began to introduce modern western magnetic knowledge to China.

In the pre-Qin era, our ancestors have accumulated a lot of knowledge in this field, and they often encounter magnetite, that is, magnetite (the main component is ferroferric oxide) when exploring iron ore. These findings have long been recorded. These discoveries were first recorded in several articles in Guanzi: "There are magnets on the mountain and gold and copper under it." There are similar records in other ancient books, such as Shan Hai Jing. The iron-absorbing characteristics of magnets have long been discovered. The main chapter of the nine volumes of Lu's Spring and Autumn Annals is: "Kindly absorb iron, or absorb it." At that time, people called "magnetism" "kindness". They think that magnets attract iron is the attraction of loving mothers to their children. And think: "Stone is the mother of iron, but there are two kinds of stones: kind and unkind. Kindness can attract his children, but not kindness. " It is said that after Qin Shihuang unified the six countries, Epang Palace was built near Xianyang. There is a door made of magnets in the palace. If someone wears armor and hides weapons to assassinate in the palace, they will be attracted by the magnet door. This story tells us that the ancient working people mastered the knowledge of magnetism very early.

When two magnets are put together and close to each other, sometimes they attract each other and sometimes they repel each other. As we all know, a magnet has two poles, one is called N pole and the other is called S pole. Like-sex repulsion, opposites attract. People didn't know this truth at that time, but they could still perceive this phenomenon.

In the Western Han Dynasty, there was an alchemist named Luan Da. He used this characteristic of magnet to make something similar to two chess pieces. By adjusting the mutual position of the polarities of two chess pieces, sometimes the two chess pieces attract each other and sometimes repel each other. Luan Da called it "playing chess". He dedicated the novel to Emperor Wu of the Han Dynasty and gave a live demonstration. Emperor Wu of the Han Dynasty was pleasantly surprised. He was named "General Five Blessingg". Luan made great use of the properties of magnets to make novel things to deceive Emperor Wu of Han Dynasty.

The ancestor of the compass appeared in the Warring States period. It is made of natural magnets. It looks like a spoon with a round bottom, which can be balanced on a smooth "field" and can rotate freely. When it is at rest, the handle of the spoon will point to the south. The ancients called it "Sina", and in the book Han Feizi at that time, there was: "Wang Li Sina took the time first." "Sooner or later" means square, east. Guiguzi recorded the application of Sina, and Zheng people took Sina with them when picking jade to make sure they didn't get lost.

In the Spring and Autumn Period, nephrite and jadeite with hardness of 5-7 degrees can be polished into various shapes, so natural magnets with hardness of only 5.5-6.5 degrees can also be used to make SiNa. In the book Lun Heng, Wang Chong of the Eastern Han Dynasty made a clear record of the shape and usage of Sina. Sina is made of a whole natural magnet after pondering. The handle of the spoon is guided by the pole, so that the center of gravity of the whole spoon falls right in the middle of the bottom of the spoon. The spoon is placed in a smooth field, surrounded by a four-dimensional stem and branches, which synthesize 24 directions. This design was completed through long-term research after the ancients carefully observed many phenomena related to magnetism in nature and accumulated a lot of knowledge and experience. The appearance of Sina is the practical application of people's understanding of the polarity of magnet fingers. However, Sina also has many defects. Natural magnets are hard to find, and they are easy to lose their magnetism when they are impacted and heated during processing. Therefore, Sina's magnetism is relatively weak, and the contact with the site should be very smooth, otherwise it will be difficult to rotate because of too much friction and resistance, and the expected guiding effect will not be achieved. Moreover, Sina has a certain volume and weight, which is inconvenient to carry, which may be the main reason why Sina has not been widely used for a long time.

Sina consists of a bronze disc and a magnetic spoon made of a natural magnet. The bronze disc is engraved with 24 directions, and the magnetic spoon is placed on the central circular surface of the disc. When it is at rest, the tail of the spoon points to the south.

The magnetic poles at both ends of each magnet are different, one is called S pole and the other is called N pole. The earth where we live is also a huge natural magnet, with different magnetic poles in the north and south. The South Pole near the Earth's North Pole and the North Pole near the Earth's South Pole. It is precisely because the geomagnetic poles do not completely coincide with the geographical level that the geomagnetic declination phenomenon appears. As we know, like magnetic poles repel and opposite magnetic poles attract, so no matter where on the earth's surface, take a magnetic needle that can rotate freely, and its N pole will always point to the north and its S pole will always point to the south.

More than 2,000 years ago, during the Spring and Autumn Period and the Warring States Period, China had already made farm tools out of iron. When working people are looking for iron ore, they find a magnet and know that it can absorb iron.

Gunpowder:

Gunpowder was invented by an alchemist of Han nationality in Sui and Tang Dynasties in China, and it has been over 1000 years. The study of gunpowder began with the ancient Taoist alchemy. The ancients refined Dan medicine to live forever. The purpose and motive of alchemy are advanced, but its experimental method still has some advantages, which eventually led to the invention of gunpowder.

Although alchemists have mastered certain chemical methods, their direction is to seek elixir of life, and the invention of gunpowder is a by-product. An alchemist usually "crouches" sulfur, arsenic and other toxic stone medicines before use, and "crouches" means surrendering. The process of losing or reducing toxicity is called "reducing fire".

Sun Simiao, a famous doctor and alchemist in the early Tang Dynasty, wrote in the Single Crystal Sulfur Law that sulfur and saltpeter should be ground into powder and put into a silver jar or a sand jar. Dig a hole, put a pot in the hole, level the hole and fill it all around. Light three honey locust seeds that have not been eaten by insects one by one, then put them into a pot and set off fireworks with sulfur and saltpeter. When the smoke can't catch fire, stir-fry the charcoal until one-third of the charcoal is extinguished, then anneal it, wait until the mixture cools before taking it, and then subdue the fire.

In the middle Tang Dynasty, a man named Qing put forward a recipe for reducing fire in the Alum Method: "22 ounces of sulfur, 22 ounces of nitrate, and half of Aristolochia. That's the end. Mix it up. Dig a hole and put the medicine in the pot, even with the ground. Put a piece of cooked fire, marble is big, and when you put it inside, the smoke will gradually rise. " He used Aristolochia instead of Gleditsia sinensis in Sun Simiao's prescription. These two substances play a burning role instead of carbon. All the recipes for latent fire contain carbon, saltpeter should be added to sulfur, and sulfur should be added to saltpeter. This shows that the alchemist intends to burn the drug to remove its virulence. Although the alchemist knew that the mixture of sulfur, nitrate and carbon would have a fierce reaction and took measures to control the reaction speed, the fire accident in the Dan room caused by drug fire still occurred frequently.

There is a story in Tai Ping Guang Ji, which tells that in the early years of Sui Dynasty, a man named Du Chunzi visited an old man who was an alchemist. Lived there that night. Du Chunzi woke up in the middle of the night and saw "purple smoke passing through the house" in the blast furnace, and the house suddenly burned. This may be caused by the negligence of the alchemist when preparing flammable drugs.

There is also an alchemy book called "A Brief Introduction to Zhen Yuan Miao Dao", which also talks about burning people's faces and hands with fire from sulfur, saltpeter, realgar and honey, going straight to the roof and burning houses. This book warns alchemists to prevent such accidents. This shows that the alchemists in the Tang Dynasty mastered a very important experience, that is, sulfur, nitrate and carbon can form a highly flammable medicine, which is called "gunpowder", that is, gunpowder. Because of the invention of gunpowder, it was once regarded as medicine in the process of self-made Dan dispensing.

"A Record of Ming Taizu": "On December 20th, the second year of the apocalypse, Huang Hemeng, a traffic general sent by Mao Zedong (Yuan Keli), the commander-in-chief of Liaoning Province, paid for food, cloth, weapons, gunpowder and other things, and then presented them with stamps and flags to show his gratitude."

Compendium of Materia Medica mentions that gunpowder can cure sores, tinea, insects, dampness and epidemics. Gunpowder can't solve the problem of immortality, and it is easy to catch fire. The alchemist is not interested in him. The formula of gunpowder was transferred from an alchemist to a strategist and became one of the black gunpowder in four great inventions of ancient china.

Spherical powder is wrapped around the head of the arrow shaft. After the fuse is lit, use a bow and arrow to shoot the gunpowder and burn the enemy. There are also gunpowder and poison, plus some asphalt and tung oil. Made into poison pills, burned and shot the enemy with bows and arrows, becoming the "enemy of ten thousand people." In the Song Dynasty, people put gunpowder into bamboo tubes, tied tiny "directional sticks" behind the gunpowder, and ignited the nitrate on the fire tube, so that the gunpowder in the tube burned rapidly, generating forward thrust and making it fly to the enemy line to explode. This is the world's first gunpowder rocket. Later, muskets and guns were invented. These are primitive tubular firearms made of bamboo. They are the ancestors of modern guns.

Print:

Block printing: It is reported that Bi Sheng invented clay movable type printing in the Northern Song Dynasty, which is considered as the earliest movable type printing technology in the world. However, the movable type printing in the four great inventions is not the predecessor of modern printing, and according to Needham, the movable type printing in the Northern Song Dynasty has many disadvantages.

At present, the earliest woodcut print is a Sanskrit version of Dalagni Jing, printed on linen paper, published in 650-670, and unearthed in the Tang Mausoleum near Xi 'an in 1974. 1966, archaeologists discovered a miniature Dalagni Buddhist sutra in South Korea, which contained the Handwriting of Zetian promulgated by Empress Wu Zetian in the Tang Dynasty (about 690 -705). Scholars infer that the sutra was not earlier than 704, and later it was treasured in a stupa built in the era of Silla in 75 1 year. However, the earliest known printed book of general size is the Diamond Sutra published in the Tang Dynasty (6 18 -907). The longitude is 5. 18 m (17 ft), and the scroll format can be traced back to September 15 of the lunar calendar in Xian Tong, Tang Yizong (that is, in 868). Scholars Joseph Needham and Qian Cunxun described the calligraphy carving of the Diamond Sutra as far more advanced and exquisite than the one-page version of the Great Rani Sutra published earlier. In addition, the two oldest printed lunar calendar dates are 877 and 882, which were discovered in Dunhuang, a Buddhist holy place at that time.

Movable type printing: Shen Kuo, a scientist and politician in the Northern Song Dynasty, once wrote an article called "Folkboard" in Meng Xi Talk, which introduced the whole process of movable type printing in detail, which was easy to understand and very detailed. In his book "Talking about Meng Xi" written by 1088, he attributed this invention to an unknown craftsman Bi Sheng (990-105 1). Shen Kuo used sintered clay characters to describe the glyphs made by Bi Sheng, arranged the characters, printed them, and took them apart for later use. Bi Sheng tried wooden movable type, but it was not until Yuan Dynasty (1368) that Wang Zhen's wooden model (active in 127 1368) became more and more perfect. Wang Zhen also put Chinese characters on a wheeled typesetting tray with a small cell according to the phonological combination, which is convenient for taking Chinese characters. As for copperplate movable type, it was not until the Ming Dynasty (1368-1644) that Hua Xiang's printed works (1439 to 15 13) became perfect.

Wooden movable type:

Wang Zhen, a famous agronomist and mechanic in Yuan Dynasty, made clear the wooden movable type and created a relatively simple turntable typesetting method suitable for the complex characteristics of Chinese characters. Later, metal movable type was invented and movable type printing was improved. Printed prints of the Tang Dynasty spread to Japan. In the late 8th century, Dalagni classics were completed in Japan, and then spread to Korea, the Middle East and Eastern Europe. /kloc-In the 5th century, Germans learned to cast characters with alloys, and movable type printing pioneered by Bi Sheng became popular in Europe.