After raising the beam, a hollow brass cylinder is suspended from one end of the beam and underneath that a rod whose capacity is exactly the same as the former is attached. These are balanced by counterweights attached to the other end of the beam.

If the beam is then lowered so that the solid cylinder is completely immersed in the water contained in a recipient placed underneath it, the balance overflows on the opposite side; on filling the hollow cylinder to the top with water, equilibrium is restored.

In this way it is verified, simply and effectively from the teaching standpoint, that a body immersed in a liquid receives an upward thrust equal to the weight of the liquid that the body displaces.