INDUSTRIAL AND ENGINEERING CHEMISTRY
396
phases, even if they form mixed crystals, cannot be treated by these methods because equilibrium is reached so slowly. Either or both of the constituents to be separated may, however, be solid. The case of liquid and vapor, unless the interchange of material is very small, is usually accompanied by such considerable heat effects that the simple procedure is not satisfactory, and a solid diagram is required. If the quantity 3f one constit
