The ultrasonic velocity and refractive index of the two ternary (benze
ne + cyclohexane + toluene and benzene + carbon tetrachloride + toluen
e) and six of their binary combinations have been measured experimenta
lly. The excess values of these properties are calculated and the resu
lts are discussed in the light of a theoretical model developed recent
ly. The agreement between experimental and theoretical values of all t
he excess properties is found to be quite reasonable.