Experimental surface-tension data for pure substances have been correlated successfully by the use of two recent modifications of the principle of corresponding states. The results are expressed in terms of simple analytical relations which allow one to calculate the surface-tension curves either from the critical constants P,, V , , and T , or from P,, T,, and the boiling point TI, and also provide a method for estimating critical properties from surface-tension measurements. In addition, a method for estimating the surface tension of molten metals is suggested.