Nuclear Susceptibility of Superfluid $B$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$

We have measured the reduced susceptibility of superfluid $B$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$ using pulsed NMR techniques at melting pressures. These measurements, which extend from $\frac{T}{T_c}=0.77\mathrm{}$ to $\frac{T}{T_c}=0.39\mathrm{}$, support the continuous-wave NMR results of Osheroff. Values of $\frac{{\rho }_s}{\rho }$ deduced from these susceptibility values are shown to agree well with fourth-sound measurements of $\frac{{\rho }_s}{\rho }$ and theoretical calculations. From these agreements we conclude that $B$-${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is well described by existing theory to quite low temperatures.