Describes a procedure applicable up to 2015 degrees Celsius, by which a pyramidal test cone is heated according to a specified schedule alongside standard cones and the softening behaviour compared. Temperature equivalents are tabulated for PCE tests expected to have an end-point of Orton cone numbers from 12 to 26, and above 26. The procedure covers preparation of test cone, cone plaque arrangement, mounting of cones on plaque. Cone height on plaque is specified.