A new system for measuring sound velocity change in liquid is described. The experiment with water as a function of temperature has been demonstrated to clarify the effectiveness of the system. As a result, resolution of sound velocity change better than 10-4 has been established with the system.

A new pulse-interferometric system which introduces the Maximum Entropy Method (MEM) has been constructed to measure sound velocity in liquids. With this system, a measurement accuracy better than 0.1% with a sample volume of 3 cc at a frequency of 5 MHz has been attained.