Measurements of the thermal expansion of cast and rolled zinc

The coefficients of expansion of cast and rolled zinc are measured under conditions of steady and of continuously increasing temperature, and marked differences between the coefficients are found to occur. On rolling, the random orientation of crystals in the cast specimen is broken up and most of the long axes are set perpendicular to the plane of rolling. No change is produced in the volume coefficient by rolling. When the zinc crystals are small, the continuous expansion is also small but as the size of the crystals increases, the continuous expansion also increases. Discontinuities in the continuous expansion are traced to the long axis of the crystals.