Measurements have been made of the ultrasonic velocity in thirty-four organic liquids over a temperature range of 0−60°C by use of a variable-path ultrasonic interferometer operating at 500,000 cycles per second. For all of the liquids studied the relation between velocity and temperature was found to be essentially linear. Values of density, adiabatic compressibility, and temperature coefficient (ΔV/ΔT) are also reported. It was found that the successive substitution of a heavier atom in a molecule leads to successively smaller temperature coefficients. It is pointed out that the temperature coefficient of ultrasonic velocity appears to be inversely proportional to the square root of the molecular weight, to a fair degree of accuracy.

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