Microscopic mass formulas.

By assuming the existence of a pseudopotential smooth enough to do Hartree-Fock variations and good enough to describe nuclear structure, we construct mass formulas that rely on general scaling arguments and on a schematic reading of shell model calculations. Fits to 1751 known binding energies for {ital N},{ital Z}{ge}8 lead to rms errors of 375 keV with 28 parameters. Tests of the extrapolation properties are passed successfully. The Bethe-Weizsaecker formula is shown to be the asymptotic limit of the present one(s). The surface energy of nuclear matter turns out to be probably smaller than currently accepted.