Abstract: The single horizontal tube evaporator we used for investigation, being described in a preceeding paper[1], was modified with a vacuum system in order to operate the boiling experiments under diminished pressures. Binary liquid mixtures employed are:- (1) Water-ethanol; (2) Benzene-toluene. Range of experiments:- (1) Heat load, 4 = 4,000 40,000 kcal/m2:hr:(C) (2) Operating pressure, p = 200 760 mm. Hg. (3) Compositions of binary liquid mixtures. A) Benzene % in benzene-toluene system:- 0%, 12%, 25%, 50%, 75%, 88%, 100%, B) Ethanol % in vvater-ethanol system:- 5%, 25%, 60%, 91.8%. The boiling beat transfer coefficients of water under various pressures were examined as preliminary experiments, the results may be correlated as follows:- a=4.0 p0.2 q0.69 For pure benzene, we obtained the following-empirical formula,- and for pure toluene,- The heat transfer coefficients of boiling mixtures of different compositions, and under different pressures were correlated with dimensionless groups suggested by ; we propose that his original equation, can be used for binary liquid mixtures in the following modified form,- with error less than ±10%. We also correlated our experimental results with C. C.equation,- for binary liquid mixtures, we propose the following modified form, with error around (+)10%.