Pressure effect on the melting temperature

Pressure-melting temperature relationship is proposed and tested against the experiments of metals (Pt and Al), salt (NaCl), and ceramic (MgO) with positive results. The equation contains one open parameter which remains constant for the investigated substances. The constant value of the parameter indicates that the presented equation for the melting curve might be the first one which does not contain any arbitrary constant which is left open to fit to the experiments.