An experiment is described in which a torsional hydromagnetic wave is excited in a cylindrical hydrogen plasma. The theory of the wave is briefly described and expressions are derived for the wave velocity, attenuation, field distributions, and the tube input impedance. Measurements are presented which verify the linear dependence of wave velocity on magnetic field and show fairly good agreement with theory for variation of mass density. The temperature of the plasma is determined experimentally by a direct resistivity measurement, and is found to agree well with the observed temperature derived from wave damping. The variation of attenuation constant with magnetic field is shown to be consistent with theory. Reflections of the waves occurring from insulating and conducting boundaries, and from a plasma-neutral gas interface are described. In all cases the phase changes at reflection are in agreeand from a plasma-neutral gas interface are described. In all cases the phase changes at reflection are in agreement with theory. The radial magnetic field distributions are experimentally investigated and compared to theoretical predictions based on a modal analysis of the driving pulse. A description is given of the plasma preparation process and of measurements of the plasma properties, which show that themore » plasma is >85% ionized with an ion density >5 x 10/sup 1//sup 5/ cm/sup -// sup 3/ and has a temperature of about 12,000 deg K. (auth) « less