The HIGH PRESSURE BOYLE'S LAW is performed at higher pressures. Mercury is not used. A small high pressure container contains a safe coloured fluid and, when the pressure in the container is raised by a small air pump the pressure is read on a gauge and the fluid is pushed up the heavy walled glass tube. The air volume in the glass tube is reduced as the pressure rises. An adjustable pointer can be clamped at any point along the scale to indicate the starting volume. Calculations are made relevant to the pressure and volume to prove Boyle's Law. The kit is complete with air pump and coloured fluid. The PDF file provides experiment information and more detail