Calorimetric measurements of excess molar enthalpies at the temperature 298.15 K are reported for the ternary mixtures [x(1)CH(3)(CH2)(v-2)CH3 + x(2)(CH3)(3)COCH3 + (1 - x(1) - x(2)){(CH3)(2)CH}(2)O] with v = 7 and 10. Smooth representations of the results are described and used to construct constant-enthalpy contours on Roozeboom diagrams. Comparisons with estimates based on the Flory theory are also presented.