Isospin Dependence of the Microscopic Optical Model for Nucleon Scattering

New experimental data for the elastic scattering of 7-24-MeV neutrons from ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ are presented, and a microscopic folding-model study of neutron and proton elastic scattering data for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at energies below 60 MeV is made to examine the isospin dependence of an effective interaction derived from nuclear-matter calculations. The theoretically derived interaction yields reasonable agreement with the data if the Coulomb potential is treated properly.