The boiling-point diagram for binary mixtures can be used to represent multicomponent equilibria and flash vaporizations (N-dimensional problems) by replacing x(i) and y(i) by the sets of {xi} and {y(i)}, respectively. The equations far binary mixtures of A and B (i = A, B) are shown to carry over to the multicomponent mixtures (i = 1, 2, ..., c). Although this qualitative geometrical representation is quantitative only at limiting values of the sets, it does provide a convenient way of representing these complex N-dimensional space relationships in 2-dimensional space.