  We measure the magnetic field dependence of the frequency and damping time
for the radial breathing mode of an optically trapped, Fermi gas of $^6$Li
atoms near a Feshbach resonance. The measurements address the apparent
discrepancy between the results of Kinast et al., [Phys. Rev. Lett. {\bf 92},
150402 (2004)] and those of Bartenstein et al., [Phys. Rev. Lett. {\bf 92},
203201 (2004)]. Over the range of magnetic field from 770 G to 910 G, the
measurements confirm the results of Kinast et al. Close to resonance, the
measured frequencies are in excellent agreement with predictions for a unitary
hydrodynamic gas. At a field of 925 G, the measured frequency begins to
decrease below predictions. For fields near 1080 G, we observe a breakdown of
hydrodynamic behavior, which is manifested by a sharp increase in frequency and
damping rate. The observed breakdown is in qualitative agreement with the sharp
transition observed by Bartenstein et al., at 910 G.
