If the baroscope is placed under the bell of a pneumatic machine and a vacuum is created, it is seen that the beam dips on the side of the ball.
It is thus demonstrated that in air the ball, which displaces a larger volume of air than does the counterweight, receives an upward thrust greater than that received by the counterweight.
If a gas denser than air is introduced into the bell, it is observed that the beam dips to the other side, thus demonstrating that the thrust received by a body immersed in a gas depends on the density of the gas and is greater in gases having major density.