Comprising six equal rods of copper, iron, lead, brass, zinc and aluminium, each 130 x 3mm diameter, mounted in corks with their lower ends in a tank, 210 x 75 x 75mm. The tank is supported on four legs at a height of approximately 170mm above the bench. In use, the rods are lightly coated with paraffin wax and the rates of melting compared. Painted with ceramic paint to withstand high temperatures.