pyridine-borane

Crossbow, its main use cover for battle formation and hunting.
In battle formation, the function of crossbow is the key. It can fire arrows and attack from a distance, which can cause damage to the enemy from a long distance compared to hand-to-hand combat or short-hand combat. In ancient times on the battlefield, the two armies confronted each other, and the crossbowmen lined up and fired, and the arrows and stones were like rain, which could frustrate the enemy's spirit and disrupt the enemy's formation. The power and accuracy of its launch are considerable, and it can be used against important targets such as enemy generals and elite soldiers, causing the enemy's command system to be disordered and combat effectiveness to be damaged. And the operation of the crossbow is relatively simple, and a person with a little training can use it. It can form a certain combat effectiveness in a short time, so it is a weapon for the army to fight.
As for hunting, crossbows also have many advantages. In the mountains and forests, wild animals are infested, and they can be hunted with crossbows. They can be launched quietly in hidden places, so as not to alarm the prey too early and improve the success rate of capture. Its range and power are enough to deal with common prey, whether it is running deer, or sly fox and rabbit, etc., it can be effectively controlled.
In addition, in some guarded areas, such as passages, castles, etc., crossbows can also be used as defensive equipment. When foreign enemies invade, with the long-range shooting ability of crossbows, they can be rejected outside the city gates and city walls, gaining time and creating advantages for their own defense. In some small-scale conflicts or public security maintenance, crossbows can also play a role in deterring lawbreakers and maintaining local peace.
Overall, crossbows played an important role in ancient warfare, hunting, and defense, and were an extremely important device at that time.

Those who weigh the weight, its physical rationality can be investigated. The weight of the earth is hard, and more of it is made of gold. Those who often weigh it are like gold. Its density is very high. This is because it needs to be small and bear a certain weight. It is necessary to measure.
In terms of self-density, the density of the weight is greater than that of water, so if you put it in water, it will sink to the bottom. This characteristic also makes it on the scale. It can be balanced by its own weight.
Furthermore, the weight of the scale has a fixed amount. The alternation of cold and summer, or the environment, the amount of change. This is the foundation of the fine measurement of the weight. If the measurement is easy, the result of the measurement will be lost.
The shape of the scale, multi-dimensional, or, or, or, there are also square ones. This is not easy to hold in hand, and it is placed on the scale to maintain balance and stability, so as not to flip obliquely, and the impact is measured.
And the surface of the scale is smoother, which is less friction. For the smoothness of the scale, the smoothing surface can reduce the friction of the scale, so that the scale can be moved, and it is also conducive to fine finishing, so as to obtain fine weighing results.
In addition, the scale is small, but its physical reasons, such as high density, fixed measurement, shaping and smooth surface, are all important for measurement.

When it comes to hiding and using ice, many things need to be paid attention to.
When hiding ice, the first heavy ice source. Ice should be taken from a clean place. If the ice source is unclean, the ice may contain filth and germs, which will cause poor ice quality and be harmful to use. Therefore, when looking for the source, look for the clear spring and clean lake, and collect it in winter when the ice is thick and solid, so as to keep the ice pure and solid.
The place where ice is hidden also needs to be carefully studied. The construction of an ice room is suitable for high and dry places to prevent the earth gas from invading and causing the ice to melt easily. The walls of the ice room should be thick and tight, so that it can be heated from the outside world. The room is covered with straw, a reed mat, etc., to help insulate. Hide ice inside, stack it layer by layer, and divide it with straw mats, so that the ice does not stick to each other and dissipates heat evenly.
As for the use of ice, there are also many points. When using ice to keep food fresh, you need to pay attention to the isolation of ice and food. If the ice is in direct contact with the food, it may cause the food to get damp and odor. You can use bamboo baskets, clay pots, etc. to hold food and place it on the side of the ice to keep it fresh by the cold of the ice. It should not be used to cool down. If people are in a cold place for a long time, or suffer from cold, it will damage the body. Therefore, when using ice to cool down, it should be enough, and pay attention to indoor ventilation to allow air circulation.
The use of ice should also be done according to etiquette. In ancient times, ice was a precious thing and could not be obtained by anyone. When using ice according to status and occasion, it should not be overstepped. On solemn occasions such as sacrifices and banquets, the use of ice is customized, and it is necessary to strictly abide by the rules to show etiquette.
Hiding and using ice, whether it is the choice of ice source, the construction of ice room, or the method of use and etiquette norms, it is necessary to pay careful attention to make the best use of ice without causing trouble.

If you want to make a bow and crossbow, there are various methods. The ancient good workmanship is the system of bow and crossbow, and the fine review is prepared, and the method can be learned from below.
The material of the bow and crossbow is the key. The bow stem is preferably made of zhe wood, which is tough in quality and has strong elasticity. If there is no zhe wood, mulberry, orange, papaya and other trees can also be replaced, but it is necessary to choose the one with a straight texture and a dense texture. The material of wood must be obtained in autumn and winter, when the wood liquid converges and the material is solid.
The tendons are tied to the strength of the bow and crossbow. Often take beef tendons and deer tendons, soak them in tung oil, and wait for several months until they are smooth and tough before they can be used. When dipping the tendons, it is necessary to turn them often to make the oil evenly soaked.
Glue is used to glue the stem of the bow and the tendons. In the past, fish bladder glue was often used, which was very sticky. The method of making glue is to take the swim bladder, wash it, put it in a pot, cook it slowly, and stir it constantly. Only when it becomes thick can it be used.
In the production of the bow and crossbow, the stem of the bow should be treated first. Cut the selected wood into the desired shape, and roast it slightly with fire, so that it is slightly bent to fit the strength of the human arm. When roasting wood, the heat must be appropriate, and if it is too hot, it will be difficult to form its shape.
The second reinforcement is applied to the bow stem, and it is glued together, so that the tendons and the bow stem are tightly fitted without the slightest gap. After bonding, tie it with a thin rope, and wait for the glue to dry.
As for the crossbow machine, it is better to cast it in bronze. When casting the machine, it is necessary to be skilled in the process, so that the size of each part is accurate and the fit is perfect. The crossbow teeth, crossbow, hanging knives and other parts need to be carefully made to make them flexible and durable.
String, twisted with silk thread or twine, the thickness is moderate, tough and elastic. When twisting the string, the force must be uniform to make the string elastic and consistent.
To be made of the crossbow, it is still necessary to test its performance. If the force is insufficient, it is necessary to adjust the curvature of the bow stem or increase the amount of tendons; if the range is inaccurate, it is necessary to check the parts of the crossbow machine and see if there is any deviation.
Ancient crossbow production is complicated and requires craftsmen to study it carefully to become a good weapon. Every process is related to the performance of the crossbow and cannot be slack.

When it comes to the process used by the god of snakes, the concern for safety during the process cannot be ignored.
The god of snakes controls the spirit snakes with extraordinary strength. However, in the process of using it, the first to bear the brunt is the snake's strong nature and it is difficult to tame. The spirit snake is inherently wild, and if it is controlled by a little carelessness, the snake's nature will be greatly developed, and it will devour its master, and its life will be in danger. Although the god of snakes has great powers, he needs to be vigilant at all times. If he controls it with spiritual skills, if there is a slight mistake, it will become a big disaster.
Furthermore, the place where the spell is cast is of great significance. The technique of using snakes, whether at the top of the mountain or in the depths of the forest, is a dangerous place. Above the mountains, the terrain is steep, the wind and clouds are unpredictable, and if you are not careful, you will be smashed to pieces if you miss your foot; in the secluded forest, miasma is pervasive, and poisons are overgrown. If you are not well protected, you will be invaded by poisonous gas, injured by poisons, and your life will be endangered.
And the method of using snakes requires a lot of spiritual power. Every time you cast a spell, the loss of spiritual power is huge. If the spiritual power does not continue, not only will the snake not be controlled, but the snake operator himself will also suffer backlash due to the depletion of spiritual power, causing damage to the primordial spirit, a drop in cultivation, and even the soul will be scattered.
In the process of manipulating snakes, it is easy to cause changes in the world and attract others to spy. There are many people in the world who covet the technique of manipulating snakes. Once they detect it, At that time, the God of Snake-Manipulating not only had to control the spirit snake, but also had to be on guard against others, and it was dangerous.
Therefore, in the process of controlling the snake, the God of Snake-Manipulating faced many safety risks such as the backlash of the snake, the dangerous terrain, the loss of spiritual power, and the coveting of others.