The acoustical resonance method was applied to steel and aluminium cylinders over a range of stiffness ratios from 0 to 1.0. The resonant frequencies for longitudinal, torsional and flexural modes of vibrations were obtained and correlated with existing theories, yielding values of Young's and shear moduli and Poisson's ratio. The Love-Rayleigh approximation was found to yield a Young's modulus value 6% lower than that calculated from Bancroft's solution of the Pochharomer-Chree theory for a d/l ratio of 1.0. The experimental data were found to be in almost exact agreement with the latter theory, yielding a Poisson's ratio value of 0.28 for steel and 0:​35 for aluminium. The shear constant K' was evaluated on the requirement of satisfying both Goens' solution of Timoshenko's equation and Pickett's solution of Pochhammer's theory. The correction factors T_n obtained from Goens' solution were found to agree within 0.15% with those calculated from Picket t^sT solution of the more exact theory. However, Goens' theory was found to have a limited range of validity depending on the order of the flexural vibrations and the d/l, ratio. However, it was found to hold remarkably well over the whole range of stiffness ratios 0 to 1.0 at least for the fundamental and first overtone of flexural vibrations. The values of Young's modulus as determined from longitudinal and flexural frequencies were found to be accurate within 3%. Some frequencies were recorded that could not be identified with any mode. Those appeared to occur near an Ω value of 2.1, where Ω = 2πfa/v_s, a is the bar radius, and v_s is the shear-wave velocity.