Abstract
An ultrasonic cw resonance technique for the measurement of the velocity of sound in solids is described. The end correction due to the presence of the transducer and coupling film can be calculated from consideration of a transmission‐line equivalent circuit. An experimental comparison is made of the cw and two pulse techniques over the frequency range 5 to 45 Mc. Application of the cw resonance technique is made to the measurement of the room‐temperature adiabatic elastic constants of single crystals of RbBr, RbI, CsBr, and CsI. A tabulation of the important elastic properties of these crystals is presented.