Ancient China did have an understanding of air pressure and water pressure, and the year of understanding was very early.

In the Western Han Dynasty, there is a book called "Huainan Honglie", which is a Taoist book also known as "Huainan Zi", and the master of compiling this book is Liu An, the king of Huainan, who died in the defeat of Liu Che, the emperor of the Han Dynasty, committed suicide, and he invented tofu.

He has many disciples, this Taoist book is a summary of his knowledge with the disciples, in addition to tofu, Liu An also did experiments on air pressure - copper urn thunder.

He sealed the copper urn containing boiling water and threw it into the well, and the boiling water in the urn cooled, and the air pressure and water pressure squeezed the copper urn through, and the huge sound of the copper urn breaking spread from the well like thunder.

In Ban Gu's "Book of Han", another story is recorded, about Wang Mang, someone took a big bird feather as two wings, the head and body were covered with feathers, through the ring button, flying hundreds of steps.

The superficial explorations of the ancestors were all finalized by experiments, but there was no quantitative analysis and research, so experiments could not be turned into theories, and it was even more difficult to develop into practical disciplines.

But now it's okay, especially after Chen Mu ordered Chang Sheng to gather enough craftsmen, they can make anything they want, and the craftsmen can make the model exactly in one day.

A wooden barrel with a lid at the middle height, the two openings of the lid are one large and one small are piled upwards, when the water is filled with water higher than the lid, Chen Mu uses a square wooden block of the same size as the large opening to tightly stuff one end of the opening, and the water on the other side will naturally overflow, and the weight of the spilled water is almost the same as the weight of the wooden block after measurement.

Chen Mu knew that this was not a common sense of science, and now he told this truth to others, and in the hands of Zhao Shizhen and Zou Yuanbiao, it became science.

Experimenting, measuring, analyzing, and summarizing, they believe that in a sealed state, multiple forces are applied to one end of the water flow, and the other end will conduct the same amount of force, and by extension, the water pressure is the same everywhere in the closed liquid.

In this experiment, they used the unit of mechanics 'Ji' and summarized the principle as 'balance'.

The so-called 'balance' comes from the summary of leverage in the "Book of Ink": balance, which is heavier on its side, must be hammered, and the weight is similar. Balanced, the short standard is long. If the two additions are similar, the bid must be lowered, and the bid will be right.

Chen Mu's annotation is: save effort and distance.

"We can make a hydraulic press."

Chen Mu instructed Xu Wei to draw a new composition with the help of a ruler and other tools to send it to the Ordnance Bureau, and soon the wooden parts were made, including two wooden water tanks, one square and one round, as well as the square wooden pipe in the middle, all closed positions were reinforced with multiple mortise and tenon structures and wound with small iron hoops on the outside.

The square water tank is large, which is the main force tank, and the square iron block is jacked up after the water is filled on it; The round cylinder connected to the square cylinder is a small cylinder of conductive force, and the upper part is a cylinder, and the piston inside can only be pushed down by the air, but not upward.

The piston only inhales and does not exhale, and finally is a relatively long and thick force arm as a whole, and the tail end of the force arm hangs an eight-tael weighing stone, the weighing stone is cast very exquisitely, and the front is engraved with the inscription "eight taels" on the reverse side of the inscription "one auspicious".

Zhao Shizhen's eyes were full of disgust when he looked at this thing, and what made him most ashamed was not this weighing stone with a special meaning, but even the handwriting engraved on it was his, his!

And he swore that he had never written these four words, and when he first saw this kind of half-catty scale, he was extremely angry, and wondered where the carver got these scales made by his own handwriting, and he ...... again and again Well, in fact, there was no pressing, and the craftsman generously told him the source.

The Oriental Marshal took the four pieces of paper cut out of the letter and asked him to engrave it.

Cut it out, cut it out and carve it ...... With this kind of chief, it can be regarded as eight lifetimes of blood mold.

The initiator did not have the consciousness of basing happiness on Chang Ji's pain at all, clapped his hands and praised the exquisite workmanship of the scales, and pulled Zou Yuanbiao to squat in front of the machine that just made it look like a big table, looking at the movement, and his mouth was still non-stop: "After our calculations, this machine has to use one Ji of force each time, and after this weighing rod, the final force input into the cylinder is ten Ji." ”

"Tsk, it's five pounds, interesting, right?"

Zhao Shizhen stood on the threshold with his arms crossed in a huff, his nose was like a cow, but neither of them paid attention to him, and looked at the machine with bare eyebrows.

Zou Yuanbiao answered: "The surface of the small water tank is the eleventh of the big water tank, doesn't it mean that this auspicious stone can be pushed up and down ten times, and you can push up fifty catties of iron, handsome, this is Yilang, amazing!" ”

"Ji Yan?" Chen Mu, who was squatting on the ground and had no manners at all, patted his knees and said: "This name is good, and ah, these two sides will be called input and output in the future, hurry up, go to Jitong!" ”

Zou Yuanbiao rolled up his sleeves and put the small Ji Tong up, again and again, seeing the iron being lifted up little by little, just when the two were about to celebrate with the crown, there was a bang, and the water splashed Chen Mu's body.

The wooden water tank itself was slowly leaking, and the inside couldn't withstand the huge pressure, so the wooden pipe cracked, and the direction was just towards Chen Mu, turning the Dongyang handsome into a soup chicken in an instant.

Zhao Shizhen smiled, and Zou Yuanbiao followed on the side.

Chen Mu pursed his lips, raised his hand to wipe the water on his face, and chuckled lightly.

Their theory was correct, and the construction was not too problematic, as long as the wooden cylinder was replaced by an iron cylinder, the object could continue to be made, and if it was large enough, it might be able to make a hydraulic press that emitted a single force.

However, the biggest problem with his design was that it was going up, and if you wanted to press something, you had to have a strong metal platform on the top, which looked a bit silly, and he hadn't figured out how to properly put downward pressure on this thing.

Even if the force is a little smaller, it can be used for oil extraction or other similar items, and if it can really make a pond of hydraulic presses, it should be possible to use it for forging.

But every step in the future can be expected to be very difficult, Chen Mu has just been splashed with water, and the broken wood residue is insignificant on the robe, if he wants to change it to iron, he will open his stomach this time.

"Let the craftsman make a smaller, iron one, and there will be a lot to try later, but at least now it is very useful, if it is iron, the force is greater, and it can be used to squeeze vegetable oil."

As soon as Chen Mu spoke, Zhao Shizhen stopped laughing, and took two steps to ask someone to prepare a change of clothes for Chen Mu, but Zou Yuanbiao was still laughing until Chen Mu turned his head and looked at him gloomy: "What are you laughing at?" Chang Ji, do you say that the scale of eight taels is a bit big, let's add another unit, what is it called? ”

"Do you still need to think about it, Dashuai?"

Zhao Shizhen turned his head and was happy, raised a finger in front of his face, and said to Zou Zhixian, who had not had time to disappear from his face with a smirk: "Biao, one hundred Biao and one auspicious!" ”