At that time in the 17th century, there was a German mayor who loved science, named Greg. He was a talented soldier who, from childhood, loved to listen to the stories of Galileo; loved to read, loved science; read to the University of Leipzig. In 1621 he went to the University of Jena to study law; in 1623 he went to the University of Leiden to study mathematics and mechanics. He studied three universities, had a broad knowledge, knew astronomy, understood geography; did not know anything about mathematics, law, philosophy, etc. Therefore, he could live in military journeys; could also stand in politics; could speak more in the scientific community. He joined the army in 1631, worked as an armed engineer and worked very well. Later, he entered the political world, and in 1646

In 1654, he heard about Tory's break-up, and he heard that there were many who did not believe in the atmospheric pressure; and he heard a few people mocking Tory's break-up; and he heard that the two sides argued very fiercely, disagreed with each other, and were at odds with each other.

He rushed to find the glass pipe and mercury, and again did the Torry demolition experiment, concluding that the experiment was accurate and unmistakable; then the air in a sealed wooden barrel was drawn away, and the barrel was ¡°bumped!¡±

One day, he and his assistant made two hemispheres, with a diameter of 14 inches, or more than 30 centimeters, and invited a large group of horses to do a ¡°big experiment¡± in the outskirts of the city.

On this day of May 8th, the beautiful city of Madrid and the sunshine, all the miles, very cool, a large crowd of people surrounded by the experimental field, he shouted very excited. some say this, some say that; some support Grick, hoping that the experiment will succeed; some assert that the experiment will fail; people are discussing, are arguing; are prophesying; and others run to the experimental field in the streets, and shout:

The mayor plays the circus.

Grick and his assistant placed the medium of the copper hemisphere on the rubber ring; then filled the two hemispheres with water; then pulled out the water all out, so that the ball formed a vacuum; and finally, shrugged the head of the air mouth tightly and closed, at which point the atmosphere pressed the two hemispheres tightly together.

Greg swung his hand, and four hornets brought eight high-headed horses, each with four on both sides of the ball.

¡°Go on, go on!¡± the crowd of black pressure people on the experimental field shouted together, while punching.

Four horses and eight horses were all sweaty, but the copper ball was still silent, and Grick had to shake his hand.

Then, on the right of the two teams, the horse multiplied; the horses drank some boiling water, wiped the sweat on the forehead, and were preparing for the second performance.

Greg swung his hand again, and the experiment was even more fun. 16 horses, deadly resistant, eight horse cries loudly, whistling horses...

The crowd on the experiment, more extended the neck, a vigorous look, from time to time issued the noise of "Hi!Hi!"

Suddenly, with a loud noise of ¡°Pop!¡± and the copper ball separated into the original two halves, Grick raised the two heavy hemispheres and proudly proclaimed to everyone:

¡°Gentlemen, ladies, citizens, you should believe it, the atmospheric pressure is so great, so amazing!¡±

After the experiment, some people still do not understand why the two hemispheres can not be pulled apart, asked him, and he patiently gave a detailed explanation: ¡°On average, we put the two hemispheres tightly together, without the need for force, it will be separated. This is because the atmospheric pressure outside the inside of the ball; the balance is offset. As if there is no atmosphere. Today, after I pulled it into a vacuum, there is no atmospheric pressure outside the ball, only the atmosphere outside the ball tightly presses these two hemispheres...¡±

Through this ¡®large experiment¡¯, people finally believed that there was a vacuum; there was an atmosphere; there was pressure; the atmosphere was astonishing, but for this experiment, the mayor of Greek spent £4,000.