The change in volume on mixing for a system showing large positive deviations from ideality is examined at one temperature to pressures of lC0,OOO Ib./sq.in. Original atmospheric pressure density data and compression measurements over the entire mole fraction range for this system, acetone-carbon disulfide, are reported at 0°C. These are correlated with the semiempirical
Tait equation to yield change in volume on mixing as a function of mole fraction and pressure.This volume change is found to decrease from the maximum of 1 cc./mole at atmospheric pressure to about 0.4 cc./mole at l00,OOO Ib./sq.in. The maximum also shifts during this pressure increase from 0.53 mole fraction acetone to 0.74. Jack Winnick is at the University of Missouri, Columbia, Missouri. J. E.