Ultrasonic attenuation measurements were made in liquid carbon disulfide over a frequency range from 5 to 155 Mc at a temperature of −63°C. Further measurements were made when methyl, propyl, and butyl alcohol were added in concentrations up to 0.06 mole percent. In each case the relaxation frequency is increased linearly with the amount of alcohol added. The relaxation frequency for pureCS2is 27.8 Mc. The shifts of relaxation frequency in liquidCS2with alcohol added are:methyl alcohol 24.7 Mc/mole percentpropyl alcohol 38.7 Mc/mole percentbutyl alcohol 50.7 Mc/mole percent.The collision probabilities (P) of like and unlike molecules in the liquid as compared to the gas are unexpectedly close, (PAB/PAA)liqbeing approximately 0.65 (PAB/PAA)gas. Possible reasons for this will be considered.