At that time, scholars in Rome and Florence had a heated discussion on whether the nature "hates vacuum" and how to explain that the water pump in the mine can only lift water to 18 elbow (10.5 meter). Although Galileo did an experiment to weigh air, which proved that air has weight, he still thought that there might be "vacuum resistance". Italian scholar G.B. Baliani wrote to Galileo in 1630 and put forward the hypothesis that there may be atmospheric pressure. 1644, Torricelli and Vivian, another student of Galileo, conducted an experiment together. They use mercury instead of water. They think that mercury, which is 0/4 times heavier than water, can only make the water column rise by about114. When the glass tube is filled with mercury and inverted in a mercury container, a "Torricelli vacuum" is obtained at the upper end of the glass tube. Compared with this lamp tube, there is also a glass tube with a round glass bulb on it. Torricelli originally guessed that a large vacuum should have a large "vacuum resistance", but the mercury columns of the two tubes are the same height.

1644, he wrote to M. Rich in Rome, saying, "We live under the seabed made of atmosphere. Experiments prove that it does have weight ... ""We see a vacuum space formed ... it is external and comes from the outside. " "They are designed not only to create a vacuum, but also to create an instrument that can indicate the change of air pressure." This experiment was first successful in Italy because Rome and Florence had the most advanced glassware blowing technology at that time. After this experiment spread to western Europe, it immediately caused Pascal, gleeck and others to study atmospheric pressure.