Sound Velocity and Adiabatic Compressibility of Liquid Helium Three

Abstract

The velocity of first sound at 5 Mc/sec was measured in liquid ${\mathrm{He}}^3$ between 0.34 and 3.14°K. The results are fitted within 0.2% by the equation $u=183.9-5.98\mathrm{}{T}^2-0.130\mathrm{}{T}^3-0.00176\mathrm{}{T}^8$ (m/sec). Initial pressure coefficients of the sound velocities and a number of derived thermodynamic quantities are also reported.