Evesham Pressure Apparatus

It comprises of a wooden box with square apertures at the top, their areas being in the ratio 4:1. There is a flexible plastic membrane immediately under the top of the box. On this membrane, loose loading platforms are supported when fitted into the apertures. A gentle pressurisation of the box with a foot pump demonstrates the relationship between area and the masses. The box is provided with tubules one at each end. Supplied without loading masses and foot pump. Dimensions 400 x 750 x 25 mm, loading platforms, (a) small: 100 mm square and (b) large: 200 mm square.