LXI.The expansion of metals at high temperatures

Abstract An optical interference method, for measurements in three perpendicular directions on the same specimen, and for use up to 800° C, is described. The use of continuous temperature variation is made possible by a device for equalizing the temperature-lag of the platinum resistance thermometer and the specimen. Observations were taken during both heating and cooling of the specimen. Results are given for tin, cadmium, zinc, lead, aluminium, copper, brass, cobalt, nickel, and steel, and, where possible, the quadratic and Thiesen's relations are fitted. Tin, cadmium, and zinc show pronounced anisotropic properties; while for cobalt, nickel, and steel the coefficient of expansion curve during heating is different from that during cooling, cobalt showing a sharp peak at 450° C. on heating and at 330° C. on cooling.