Air pressure experiment. Gasparo Berti's experiment to show that a vacuum can exist in nature. The pipe at right is around eleven metres in height, the amount of water that atmospheric pressure can displace, and is sealed at the top. Its open base rests in a jar of water (bottom right). In the sphere above the column at top right, Berti placed a bell. When the system reached equilibrium, a vacuum was left in the sphere above the water column. The absence of air meant that the ringing of the bell could no longer be heard. Berti (1600-1643) performed this experiment at the Minim Convent in Pincio, Italy.