Shape of the Coexistence Curve near a Plait Point in a Three-Component System

The degree, $d$ , of the coexistence curve near the plait point in the system ethanol–water–chloroform has been determined from measurements of the volumes of coexisting phases in sealed samples. The result, $\text{d\hspace{0.17em}=\hspace{0.17em}2.67\hspace{0.17em}±\hspace{0.17em}0.12}$ , shows the deviation from the mean‐field $\text{d\hspace{0.17em}=\hspace{0.17em}2}$ and shows also the renormalization $\text{d\hspace{0.17em}=\hspace{0.17em}(1\hspace{0.17em}−\hspace{0.17em}α′)\hspace{0.17em}/\hspace{0.17em}β}$ that is predicted by current theories. ($\text{1\hspace{0.17em}/\hspace{0.17em}β}$ is the degree of the temperature‐density coexistence curve in a pure fluid and $\mathrm{\alpha \prime }$ is the index of its constant‐volume specific heat singularity.)