Mercury, alum, nitrate, and sulphur are commonly used in alchemy and pharmaceuticals, and have important uses in many fields covered in Tiangong Kaiwu.
Mercury, also known as mercury, is liquid at room temperature, has a metallic luster, and has unique properties. In alchemy, mercury is often the key raw material. The ancients believed that it could refine longevity pills. Although this concept is now known to be wrong, mercury was widely used by alchemists at that time. At the same time, in the field of ancient metallurgy, amalgamation can be used to extract metals such as gold and silver, and use mercury to form amalgam with the metal, which is then heated to evaporate the mercury to obtain pure metals. In medicine, mercury compounds have been used to treat skin diseases such as scabies, but because mercury is toxic, its use should be extremely cautious.
There are many kinds of alum, such as alum, green alum, etc. In the papermaking process, alum is a commonly used sizing agent, which can make the paper difficult to ink and improve the quality of writing and printing. In food processing, alum can be used to purify water, so that impurities in the water can condense and settle, and obtain cleaner water; it is also used in pickling food, such as adding a small amount of alum when making kimchi, which can make kimchi taste more crisp. Green alum has a wide range of uses in ancient dyeing workshops. It can be used as a mordant to help dyes better adhere to fabrics and increase dyeing fastness.
Nitrate, mainly refers to potassium nitrate. In gunpowder production, nitrate is a key ingredient, mixed with sulfur and charcoal in a specific ratio to make gunpowder. Gunpowder is widely used in the military field, changing the pattern of war. All kinds of firearms are powered by gunpowder and exert great lethality. At the same time, nitrate also has a place in ancient alchemy. Alchemists use its chemical properties to participate in the refining process of alchemy.
Sulfur, warm in nature, sour in taste, toxic. In the field of medicine, it can be used externally to detoxify insects and treat sores, and internally to replenish fire and help yang and laxative. It is often used to treat skin diseases such as scabies, baldness, and vulgaris, as well as asthma, impotence, and constipation due to deficiency and cold. In industry, sulphur is used to make sulfuric acid, which is also an indispensable substance in the vulcanization process of rubber. It can enhance the strength and elasticity of rubber and improve the properties of rubber.

Mercury is a liquid at room temperature, silver-white in color, metallic luster, heavy in quality and good in fluidity. Its density is quite high, about 13.6 times that of water, which is the highest density among metals. This property makes it easy to distinguish from other things in many occasions. Mercury has a very low melting point, minus 38 degrees, 87 degrees Celsius, and a boiling point of only 356.6 degrees Celsius. It is easily converted into a gaseous state by heat and diffuses in the air. It is silent and highly concealed. This is one end of its danger.
Bromine is also a liquid at room temperature and pressure. However, its color is red-brown, and it has a strong pungent smell. This smell is pungent and unbearable, making it uncomfortable to smell. The density of bromine is greater than that of water, about 3.1 grams per cubic centimeter. It is insoluble in water, but easily soluble in organic solvents, such as carbon tetrachloride. It is widely used in organic synthesis and other fields.
Gasoline, a mixture of various hydrocarbons, has a clear and transparent appearance, is volatile, and has a special odor. Its density is less than water, about 0.7 to 0.79 grams per cubic centimeter. It is easy to burn and releases a lot of heat energy during combustion. It is often used as fuel for vehicles and other power needs. Gasoline is highly volatile and can easily form a flammable mixture in the air. In case of open flames and hot topics, it can easily cause combustion and even explosion. The potential safety hazard should not be underestimated.
Of the three, mercury has special metallic liquid properties and high toxicity; bromine is known for its unique color, taste, and solubility; gasoline occupies a place in the energy field due to its flammability and volatility. They all have unique physical properties and have their own uses in the world.

Mercury is feminine in nature, such as mercury. It is liquid at room temperature and has a metallic luster. Its mass flows amorphous and is smooth to the touch. Mercury is highly volatile and can gradually dissipate in the air. And mercury is toxic. If it is accidentally inhaled by its vapor or absorbed through the skin, it can cause damage to the human organs, especially the liver, kidney and nervous system.
Bromine is a liquid non-metal, red-brown in color, with a strong irritating odor. It is active and highly oxidizing, and is often used as an oxidant in chemical reactions. Bromine is highly volatile, forming reddish-brown smoke, which is corrosive and has strong irritation and corrosion effects on human skin and mucous membranes.
Iodine is a purple-black solid with a metallic luster under normal conditions. Its properties are relatively stable, but it is easy to sublimate when heated, and changes directly from solid to gaseous, forming purple vapor. Iodine has a high solubility in organic solvents, which can make organic solvents show a unique color. Iodine is an essential trace element for the human body and is essential for thyroid function. Iodine deficiency can cause thyroid enlargement and other diseases. And iodine has a certain degree of oxidation, but it is weaker than bromine.
Mercury, bromine, and iodine all have unique chemical properties and are important in many fields such as industry, medicine, and scientific research. However, due to their characteristics, careful precautions should be taken when using them to ensure safety.

If you want to make a combination of mercury, alum, halogen, and sulfur, the ancient craftsmen have many methods.
The method of making mercury, often take Dan sand. For Dan sand, mercury sulfide is also. First crush the Dan sand as the end, put it in a closed vessel, and calcine it with fire. When the Dan sand is heated, it is divided into mercury and sulfur. Mercury is a liquid state and can be condensed. "Baopuzi" said: "The Dan sand is burned into mercury, and the accumulation becomes Dan sand." This is also called also.
The synthesis of alum begins with minerals such as aluminum, potassium, and iron. If alum is taken, crush it first and soak it in water, so that the soluble in it is added to the water. Then boil over fire, remove the water, and get the crude product of alum. The water is melted and recrystallized to get pure alum. There are also those who react with metal and sulfuric acid to get alum. Such as iron and sulfuric acid, heating reaction, to get green alum, its color is emerald green, and it has a wide range of uses.
The system of halogen is mostly derived from seawater. Seawater is introduced into the pool, and after sun exposure, the water is gradually removed, and the halogen is gradually thickened. When its concentration is suitable, halogen can be obtained. There are also those who take water from salt wells and boil it to remove water to get halogen. The halogen contains various salts, which can be used as a raw material for chemical industry.
The system of sulfur, one of which is taken from volcanic areas. Volcanic eruptions often carry sulfur Second, pyrite is used as raw material. Pyrite, that is, ferrous disulfide. It is crushed, calcined at high temperature, and pyrite decomposes to obtain sulfur. During the reaction, sulfur dioxide is generated, which needs to be properly handled to prevent pollution in the atmosphere.
Ancient craftsmen, in the synthesis of various things, although simple tools and little knowledge, but with diligent thinking and practice, created many methods. Today's chemistry, inheriting the foundation of ancient times, has been more refined. The method of making these four things is more delicate, efficient and environmentally friendly.

When storing and transporting mercury, sand, and tridacna, there are many matters to be paid attention to.
Mercury is a highly toxic metal that is liquid and volatile at room temperature. When storing, it must be placed in a sealed container to prevent the volatilization of mercury from escaping into the air and causing poisoning. The storage place should be kept cool, dry, and away from fire and heat sources, because mercury will evaporate rapidly when heated. When transporting mercury, the container selected must be strong and well sealed to prevent leakage. In the event of a leak, emergency measures should be taken immediately, such as sprinkling sulfur powder, so that the mercury reacts with it to form mercury sulfide, reducing its toxicity and volatility.
Sand, although relatively stable in nature, should be stored in a dry place to avoid rain initializing its loss or quality damage. The storage place should be well ventilated to prevent moisture from causing sand particles to agglomerate and affect its use. When transporting sand, it is necessary to ensure that the loading is stable to prevent it from being scattered due to bumps and shaking during transportation, which will cause pollution to roads and the surrounding environment.
Tridacna, a shell of marine life, is a rare marine protected animal product. When storing and transporting tridacna, the first priority is legality. Today, illegal hunting, killing, purchasing, transporting, and selling of precious and endangered wild animals and their products are illegal. If the storage and transportation of Tridacna are involved due to reasonable scientific research needs, relevant laws and regulations must be followed, complete procedures must be handled, and proper packaging must be carried out to avoid damage caused by collisions during transportation.