Potential density
Potential density is a dynamically important property: for static stability potential density must decrease upward. If it doesn't, a fluid parcel displaced upward finds itself lighter than its neighbors, and continues to move upward; similarly, a fluid parcel displaced downward would be heavier than its neighbors. This is true even if the density of the fluid decreases upward. In stable conditions (potential density decreasing upward) motion along surfaces of constant potential density (isopycnals) is energetically favored over flow across these surfaces (diapycnal flow), so most of the motion within a 3-D geophysical fluid takes place along these 2-D surfaces.
Methanol (data page)
Here is a similar formula from the 67th edition of the CRC handbook. Note that the form of this formula as given is a fit to the Clausius–Clapeyron equation, which is a good theoretical starting point for calculating saturation vapor pressures:
Data obtained from "Lange's Handbook of Chemistry", 10th ed. and "CRC Handbook of Chemistry and Physics" 44th ed. The annotation, "d a"°C/"b"°C, indicates density of solution at temperature "a" divided by density of pure water at temperature "b" known as specific gravity. When temperature "b" is 4 °C, density of water is 0.999972 g/mL.Except where noted otherwise, data relate to standard ambient temperature and pressure.