Consists of a metal tank 150 x 90 x 100 mm L x B x H has
six apertures on one side through which 100 x 3 mm length
x dia metal rods of copper, brass, aluminium, iron, zinc and
lead pass. The outer end of each rod had a cavity. When the
low melting point paraffin wax is placed in the cavity, the
different metals melt the paraffin at different rates.