  The first observation of fast and slow magnetocoriolis (MC) waves in a
laboratory experiment is reported. Rotating nonaxisymmetric modes arising from
a magnetized turbulent Taylor-Couette flow of liquid metal are identified as
the fast and slow MC waves by the dependence of the rotation frequency on the
applied field strength. The observed slow MC wave is damped but the observation
provides a means for predicting the onset of the Magnetorotational Instability.
