Parametric Representation of the Equation of State Near A Critical Point

A parametric representation of the usual thermodynamic variables in the neighborhood of a critical point is proposed in terms of new variables $r$ and $\theta$. The representation is chosen so that the "scaling-law" behavior is entirely contained in the $r$ dependence, the $\theta$ dependence being free of critical singularities. Preliminary calculations show that the $\theta$ dependence may be chosen to have a rather simple form both in a ferromagnet and in fluids.