The vibrations of a black hole of mass 31, perturbed from spherical symmetry, have been studied numerically. Initial perturbations of high spherical-harmonic index (1 1) which contain Fourier components of long wavelength (2irM > X 2ir314) produce long-lasting vibrations. The vibrational energy is radiated away gradually as long, nearly sinusoidal wave train of gravitational radiation with angular frequency (27)-1/2 1/31.