Shows that pressure of liquids varies with depth and is independent of the shape of the vessel. Four differently shaped glass vessels have identical bottom opening, which enables any one of them to be screwed into the outlet valve. The valve has an accurately ground disc mounted at one end of the beam, which, in turn, is carried on a pair of adjustable point pivots. The other end of the beam has provision for hanging weights. An index pointer is provided for observing liquid level in the container. The apparatus is mounted on a heavy, metal stand. Complete with plastic reservoir and a set of weights.