Abstract
Measurements were performed on the absorption and dispersion of ultrasonic waves in castor oil and the result was discussed from the standpoint of the relaxation theory of viscosity. Absorption measurement was performed by the pulse technique at three frequencies 1. 43Mc/sec, 2. 86Mc/sec and 7. 6Mc/sec, and at temperatures between -4°and+35°C. The observed absorption coefficients proved to be lower than the classical values given by the Stokes'formula. Velocity values were obtained at five frequencies between 0. 47Mc/sec and 7. 7Mc/sec by ultrasonic interferometry and revealed a dispersion of about 20m/sec between these frequency limits. This dispersion is of approximately twice the amount to be expected from the relaxation theory by empoloying the static value of the viscosity coefficient.
