A further study of light scattering in relation to sound absorption has revealed that the ratio of the intensity of the central component to the sum of the intensities of the Brillouin components is a function of total sound absorption, rather than of viscosity as interpreted from observations in liquids, or of the ratio of the specific heats only as given by Landau-Placzek theory. That it depends on both viscosity and γ as given by our formula

  • equation image

in a previous paper, has been made clear from an interpretation of the results so far obtained in light scattering. This method enables one to determine the velocity and absorption of ultrasonic waves from light scattering experiments.