Previous work has considered the effect of free body resonances on the scattering of an incident plane wave by a cylindrical target in water and has related the major features of the theoretical form function resonances to the experimentally obtained farfield reflection patterns. Excitation of these free body resonances is here observed for a glass cylinder in water utilizing a birefringence imaging technique. A fused quartz cylinder is insonified by a long plane propagating pulse and images of the internal stress pattern at resonance frequencies obtained under polarized light. The experimental data are in agreement with a normal mode theoretical computation of the resonance locations and predicted stress distributions for the particular modes.