4-bromopyridine-3-carbaldehyde

Lead and mercury are the masters of hardware, and are essential medicines for alchemy. Although the "Tiangong Kaiwu" does not elaborate on the main use of lead and mercury in alchemy, it is considered in ancient books that lead and mercury are used in the way of alchemy, and their use is essential.
Lead is heavy in nature and heavy in quality, with a silver-white color. Mercury, commonly known as mercury, is liquid at room temperature, flexible and lively. The two are often the key things in alchemy.
Ancient alchemists used lead and mercury as the basis, hoping to refine the pill of longevity. Lead is in the pill cauldron, which can be calcined by heat and can be turned into lead pills and other substances. Lead pills are red in color and have special chemical properties. The ancients believed that it has the power of tonifying, and it can be used to strengthen the body and prolong life.
Mercury is regarded as a spiritual thing because of its special form. Mercury is volatile and can form amalgam with many metals. During alchemy, mercury often cooperates with lead and other substances, and through complex chemical reactions, it is expected to refine miraculous medicinal pills.
In many alchemy classics, such as "Baopuzi Nei Pu", etc., the use of lead and mercury is described in detail. Beginning with lead and mercury, it is supplemented by other minerals and herbs, which are controlled by exquisite heat and repeatedly calcined in the pill cauldron. Or melt lead first, wait for it to be soft, add mercury, the two blend, and then go through the fire of civil and martial arts, or rise or fall, causing various changes to occur.
However, lead and mercury are toxic. Long-term use of lead and mercury-containing medicinal pills not only fails to live for long, but also causes physical damage and even endangers life. Although the ancients pursued longevity in alchemy, there are many fallacies in modern scientific views, but the important position of lead and mercury in ancient alchemy cannot be ignored, which reflects the ancients' exploration and pursuit of material changes.

Today, there are 40% saltpeter and 30% sulfur, and I want to know how to synthesize it. The combination of saltpeter and sulfur is remembered in ancient alchemy.
Where these two are combined, you should first prepare a clean device to prevent the splashing of sparks and the mixing of impurities. Choose an open and ventilated place to prevent the accumulation of poisonous gases and endanger the human body.
Take saltpeter, because of its dryness, it must be lightly ground and finely ground to form a powder, so that the particles are uniform and fine, without agglomeration. Be careful when grinding, do not let the appliance collide and generate heat and catch fire.
Take sulfur for the second time, and also grind it into a fine powder. Sulfur is soft and easy to grind, but it has a pungent taste. When grinding, cover your mouth and nose with a towel.
After grinding, place the end of the two in one vessel and stir it slowly. Stir gently, without force, to prevent the end of the medicine from flying, and to prevent heat from friction and cause the medicine to catch fire. Stir until the two are evenly mixed before the preliminary mixture is obtained.
However, this mixture still needs to be properly disposed of. Or you can add other things, such as charcoal, to adjust its properties and control its dryness. If charcoal is combined, it should also be finely ground, added slowly in an appropriate proportion, and then stirred evenly.
When combining the medicine, there should be no fireworks around. When the mixture is ready, it should be stored in a closed place in a cool and dry place, and it should not be damp or heated to prevent the drug from mutating and causing danger.
In this way, the method of synthesis of saltpeter and sulfur is required, and it is necessary to be cautious at all times.

The physical properties of lead and mercury can be particularly investigated. Lead is heavy and soft, with a silver-gray color, and is commonly found in all kinds of utensils. Its melting degree is quite low, only 327.5 degrees Celsius, and it is easy to turn into a liquid under fire. Its density is very high, reaching eleven grams per cubic centimeter. It is strange, and it feels heavy when held in hand. And lead has good electrical conductivity, although it is not as good as copper and silver, it is also quite useful in some occasions.
Mercury, commonly known as mercury, is the only metal that is liquid at room temperature. Its color is silver-white and shiny, and it looks like a spirit when flowing. The density of mercury is extremely high, about 13.6 grams per cubic centimeter. When placed on other objects, it can often sink due to its weight. Its boiling point is 357 degrees Celsius. Although it needs a hot topic to vaporize, it will slowly evaporate in the air. This point cannot be ignored. When mercury comes into contact with other objects, special phenomena often occur. For example, on glass, it will condense into a ball and be difficult to adhere. This is because of its high surface tension.
Both lead and mercury are toxic to a certain extent. Lead enters the human body, and if it accumulates for a long time, it will damage the internal organs, especially the brain and blood, causing people to be dizzy and weak. If the mercury vapor is inhaled by the human body, it can also injure the brain and kidneys, causing a trance of expression and tremor of limbs. Therefore, when taking lead and mercury, one should be cautious to prevent its harm from reaching the body. The physical properties of lead and mercury are unique, and if used inadvertently, it will cause harm to people.

"Tiangong Kaiwu" is an ancient scientific and technological masterpiece in our country. Today, it is answered in its classical Chinese genre:
Mercury, commonly known as mercury, has a unique nature. Mercury has the shape of a liquid, and at room temperature, only mercury is in the state of a liquid, which is different from the solid phase of various metals. It is smart and smooth. Its mass is heavy and its specific gravity is quite large. It is placed above other things, and it can often sink because of its weight.
The chemical activity of mercury is obvious under certain circumstances. It is volatile when heated and turns into mercury vapor, which is toxic and cannot be ignored. Mercury can combine with many metal phases to form amalgam. This property has many applications in metallurgy and other things.
When mercury meets sulfur, it can be rapidly synthesized into mercury sulfide. The change of this chemical combination, its color is often different, and it is also one of the characteristics of mercury. And mercury can exhibit unique chemical behaviors in redox reactions. In case of strong oxidizing agents, mercury can be oxidized, and its valence state is variable, either monovalent or divalent, and the properties of the compounds formed are also different.
Although mercury has unique chemical properties, its toxicity must also be taken seriously. When using and disposing of mercury, we should follow the ancient method carefully to prevent its volatilization and avoid its entry into the body, so as to ensure personal safety and protect the environment. In this way, we can make good use of the characteristics of mercury and avoid its harm.

There is a question today, what is the price range of silkworms in the market. According to the records in "Tiangong Kaiwu", the price of silkworms varies with its quality and the supply and demand of the market.
The high-quality silkworms have excellent silk quality, radiant color, flexibility and length, and can be used as raw materials for high-quality silk. In the market, their price is quite high. In the past, in the rich years, the price of the high-quality silkworms could reach about thirty taels of silver per load. If the demand for silk increases greatly, or when the silkworm production fails, the price is even more exuberant, and each load may reach forty taels of silver, or even fifty taels.
The medium-sized silkworms have good silk quality, but they are slightly inferior to the high-quality ones. In the rich years, the price of each load is about twenty taels of silver. If the market conditions change, the price may drop to fifteen taels, or rise to twenty-five taels, depending on the situation.
The lower-grade silkworms have coarse and sparse silk and are only suitable for ordinary fabrics. The price is relatively low, about ten taels of silver per load in good years. When the market is abundant in silkworms, or the demand for lower-grade silk fabrics is sluggish, the price may be as low as seven or eight taels.
To be clear, the price of silkworms is not static, and is actually controlled by many factors such as weather, geographical location, and personnel. If the weather is good, the silkworm is going well, and the output is abundant, the price may stabilize and decline; if there are disasters, such as droughts and floods, insect disasters, and the silkworm production is damaged, the price will rise. And the needs of different places are different, and the prices of production areas and sales areas are also different. And the business of the market and the guidance of government orders are all involved in the price of silkworms. Therefore, if you want to know the exact price of silkworms, when you look at the real situation in that place.