Chapter 8 Chapter Two: The Foundation Laying of Traditional Chinese Science and Technology

"Superior" is an idiom we often use, which is used to describe the perfection of kung fu.As for the source of "Perfect", the common dictionaries now say that it comes from the Taoist alchemy when the flames turn green when they succeed in alchemy, and some even add the word "superstition".In fact, this statement is wrong. In the "Kao Gong Ji" written in the late Spring and Autumn Period, there is a record about observing the change of flame color to judge the bronze smelting process, saying that when smelting bronze, the copper and tin materials will first emit black gas, " When the black and turbid air is exhausted, yellow and white are next; when yellow and white are exhausted, blue and white are next; when blue and white are exhausted, green air is next, and then they can be cast." Modern science has proved that when metal is heated, due to evaporation, decomposition, chemical combination, etc. , producing gases of different colors.When smelting bronze, the hydrocarbons attached to the raw materials will burn and produce black and turbid gas. As the furnace temperature rises, impurities such as oxides and sulfides contained in the raw materials will produce yellow-white and bluish-white gas. When it only emits green gas, it means that the impurities are basically removed, and the bronze has been smelted and can be cast.It can be seen from this that "the perfection of fire" should come from bronze smelting, not alchemy.It is an empirical summary, scientific rather than superstitious.Of course, the smelting technology is quite mature when the green gas can be used to judge the smelting of bronze.This experience has been obtained through countless production practices over a long period of time.

my country began to use copper in the late Neolithic age about four or five thousand years ago.Archaeological discoveries show that at that time, natural red copper could be processed by cold forging technology, and the initial bronze smelting technology was established.In the Shang Dynasty, bronze smelting and casting technology had reached maturity, and it was further developed during the Spring and Autumn and Warring States Periods.People can see the superb state of bronze casting technology at that time from the large number of exquisite pre-Qin bronzes unearthed, such as the Simuwuding weighing 875 kilograms and the large chime bell unearthed in Suixian, Hubei.

From a global perspective, the ancient Mesopotamians began to use natural copper about 9,000 years ago, smelted copper 6,000 years ago, and bronze 5,500 years ago; ancient Egypt began to smelt copper about 7,000 years ago. 5000 years ago there was bronze.In contrast, China's utilization of copper was much later.However, unlike other ancient civilizations, China had a long process of refining red copper, but began to smelt bronze shortly after the appearance of red copper processing, and took advantage of the low melting point of bronze and the characteristics of easy casting, so that the bronze smelting technology developed rapidly. After getting up, it quickly stepped into the world's advanced ranks and created a bronze civilization that attracted worldwide attention.

In addition to a large number of bronze wares, the symbol of the excellent bronze civilization in the pre-Qin period is also reflected in the conclusion of certain rational bronze alloy ratio rules, that is, the preparation of different proportions of bronze alloys according to the performance requirements of different uses of bronze wares.This is the "Gold has six Qi" recorded in "Kao Gong Ji", "Jin" refers to bronze, and "Qi" is the title of alloy. Bronze can be divided into copper-tin alloy, copper-lead alloy, and copper-tin-lead alloy. The "six Qi" mentioned in "Kao Gong Ji" refers to the ratio of tin bronze. "Six Qi" means "six parts of its gold and tin in one place, which is called the Qi of bells and tripods. Five parts of its gold and tin in one, it is called the Qi of ax and catty. Four parts of its gold and tin in one, it is called Ge Qi of the halberd. Three parts of the gold and tin in the first place are called the Qi of the big blade. Five parts of the gold and the tin in the second are called the Qi of cutting and killing arrows. The gold and tin are half of it, which is called the Qi of Jiansui."That is, the tin content in bronze is 16.7%, 20%, 25%, 33.3%, 40%, and 50%, respectively.This is the earliest empirical summary of the alloy ratio in the world.

Modern scientific analysis shows that bronze with a tin content of about 17% is orange-yellow, with beautiful appearance, good sound effect and good corrosion resistance, which is exactly what is needed for casting bells and tripods.As the content of tin increases, the hardness of bronze increases, but the texture is brittle and easy to break; as the content of tin decreases, the hardness of bronze decreases, but its toughness increases.Weapons such as knives, cuts, and arrows require higher hardness, so the tin content is relatively high; while tools and weapons such as axes, daggers, and halberds require certain toughness to improve service life, so the tin content is relatively high. Low.Bronze mirrors need to be polished to have a silvery white luster. They are required to be hard and not afraid of brittleness, so they contain the highest tin content.It can be seen that the "Six Qi" generally correctly reflects the proportioning law of the bronze alloy.