Many others, MM.

Cailletet and Colardeau, M.Young, M.J.Chappuis, etc., have proceeded thus.
The case of mixtures is much more complicated.

A binary mixture has a critical space instead of a critical point.

This space is comprised between two extreme temperatures, the lower corresponding to what is called the folding point, the higher to that which we call the point of contact of the mixture.

Between these two temperatures an isothermal compression yields a quantity of liquid which increases, then reaches a maximum, diminishes, and disappears.