A reverberation method for the measurement of the absorption of ultrasonics in liquids

The ultrasonic reverberation of a liquid contained in a spherical vessel of about 0.5 litres volume has been investigated experimentally over the frequency range 200 kc/s to 2 Mc/s. The time constant of acoustic exponential decay was measured by a null method in which it was balanced against an exponential waveform of known time constant generated in an RC network. The mechanism of energy loss in the vessel was investigated and this loss was allowed for by calibration of the vessel using a liquid of known absorption. The absorption was determined in a number of organic liquids and evidence of relaxation effects was observed in methyl benzoate, toluene and acetaldehyde.