Melting Curves of ${\mathrm{He}}^3$, ${\mathrm{He}}^4$, ${\mathrm{H}}_2$, ${\mathrm{D}}_2$, Ne, ${\mathrm{N}}_2$, and ${\mathrm{O}}_2$ up to 3500 kg/${\mathrm{cm}}^2$

New and more accurate measurements were made on the melting pressure-temperature relationship of seven substances below 120°K and up to 3500 kg/${\mathrm{cm}}^2$. New regions were covered for ${\mathrm{He}}^3$ and ${\mathrm{O}}_2$. The blocked-capillary method was used. The data were fitted to the Simon-type equation, $P=a+b{T}^c$, with more success than to a quadratic, $P=A+BT+C{T}^2$. Rather straightforward shifts were obtained in the melting curves of the isotope pairs, ${\mathrm{He}}^3$-${\mathrm{He}}^4$ and ${\mathrm{H}}_2$-${\mathrm{D}}_2$. Superpressuring in the ${\mathrm{O}}_2$ measurements was unusually great.