The first $\mathrm{Pb}(n, {n}^{\ensuremath{'}}x)$ data (at 65 MeV) are compared to earlier (61-66 MeV) ($p, {p}^{\ensuremath{'}}x$) data. The isovector sensitivity of these nucleon probes is used to determine $\frac{{M}_{n}}{{M}_{p}}\ensuremath{\simeq}\frac{N}{Z}=1.54$ for the giant quadrupole resonance (GQR). This result is consistent with other direct GQR measurements, ${2}_{1}^{+}$ data connected through core polarization, and several microscopic random-phase-approximation calculations, but in disagreement with a $\frac{{\ensuremath{\pi}}^{\ensuremath{-}}}{{\ensuremath{\pi}}^{+}}$ study which gives $\frac{{M}_{n}}{{M}_{p}}=3.8\ifmmode\pm\else\textpm\fi{}1.2$.