What's the story of the famous Fort Madre hemisphere?

New Experiment of Hemispheric Vacuum in Fort Madre

At that time in the17th century, there was a German mayor named otto von gehrig who loved science. He was born in Fort Madre on1October 20th, 1602, 165438. He is a well-read soldier and likes to listen to Galileo's stories since he was a child. Love reading and science; I went to Leipzig University. 162 1 year, went to the University of Jena to study law. 1623 went to Leiden University to study mathematics and mechanics. He studied in three universities, with a wide range of knowledge, including astronomy and geography. Mathematics, law, philosophy, engineering and so on. , are omniscient, omniscient. Therefore, he can live in the army; We must also gain a foothold in politics; 163 1 enlisted as an ordnance engineer in the army. Later, he joined the political circles, and 1646 was elected as the mayor of Fort Madre. No matter in the army or in the municipal government, he never stopped his scientific exploration. He often engages in various physical experiments and research in his spare time, and his main achievements are included in him. Gehrig died in Hamburg.

When otto von gehrig was in college, he began to be interested in the old arguments about "vacuum", such as what is the nature of space and how celestial bodies interact with each other through space. 1646 after knowing Descartes' argument that matter and space are equivalent and vacuum cannot exist, he decided to use experiments to verify it. He invented the air pump for the first time (1650) after improving the water pump, adding valves, changing it into copper balls and strengthening the seal, and then continuously improved it. At the same time, he conducted a series of vivid experiments on various properties of air, vacuum and atmospheric pressure, such as vacuum can not transmit sound, candles put in vacuum go out, birds and fish die. One of the most famous is 1654' s "Madeborg Hemisphere Experiment", that is, two copper hemispheres are butted together, sealed with a leather ring soaked with turpentine wax, and then evacuated. Cavalry is needed to pull the two hemispheres apart. These experiments were carried out in 1654, 1657 and 1663 in regensburg, Madeborg and Berlin respectively, which made a sensation, indicating that human beings can create a vacuum and demonstrated the great mechanical force of atmospheric pressure. It aroused extensive interest and support from the experimental science society, and encouraged christiaan huygens and Robert Boyle to conduct further research.

Otto von gehrig further studied the phenomenon that the air density changes with the ground height and humidity, invented the water column barometer, used the barometer to predict the weather changes, and put forward the systematic meteorological observation through the observation station network. He also studied geomagnetic phenomena and made a spherical model to study the magnetic attraction between celestial bodies by simulating the composition of the earth's minerals. [