AbstractThe Lydersen‐Greenkorn‐Hougen (L‐G‐H) charts correlating the isothermal pressure effects on enthalpy for pure compounds based on a modified corresponding states principle have been improved with the aid of reliable literature data. To facilitate machine computations, the improved charts, divided into the superheated vapor region, the subcooled liquid region, the saturated vapor, and the saturated liquid lines, have been expressed in analytical forms. This correlation reproduces the literature enthalpy data including those in the critical region for pure compounds with an average deviation of about 5 B.t.u./lb. It can also be used for the estimation of enthalpies of nonpolar mixtures with satisfactory results.