Abstract
The propagation of sound in suspensions of solid particles in water in the range of frequency 1 to 10 Mc/s and of particle radius 8 to 100 microns is measured. For the ultrasonic attenuation a pulse method is used, and the suspension is either monodisperse (glass spheres) or polydisperse (silica particles). In the latter suspension the particle size distribution is measured optically.
Results are compared with a theory due to Sewell and others and good agreement obtained. The ultrasonic absorption is linear with concentration up to 18% by volume. Some measurements were also made on `sediments' of glass spheres and natural sands in which the attenuation is high and increases rapidly with frequency and particle size.