A tuning fork of the metal being studied was mounted in an electric furnace and one prong was connected by means of a thread to a stylus which recorded the motion of the prong on a moving plate. Thus the frequency was measured to 1/10 percent. Curves obtained for a 3.5 percent nickel steel. and for a soft machine steel (.15 percent C) are practically identical, the modulus decreasing 10 percent as the temperature increased from 20° to 350°C and 16.7 percent for the change from 20° to 500°C. This suggests that the temperature variations of the modulus may be a fundamental property of the atoms, unaffected by the size of the crystals.

• Received 31 December 1924

DOI:https://doi.org/10.1103/PhysRev.26.121