The effect of rotation on the local pattern of melting and on the overall rates of melting and energy storage were determined experimentally for melting in a rotating horizontal tube. The tube was rotated about a vertical axis situated midway between the ends of the tube. Separate sets of experiments were performed for each of two conditions of constraint of the melting solid. In one, the solid was constrained to lie along the axis of the tube, while in the second, the solid was free to fall to the bottom of the tube. For the constrained case, the shape of the melting solid was markedly affected by rotation, but the timewise variations of the melted mass and stored energy were only moderately affected-typically in the 10% range. In the case of the unconstrained solid, the shape of the solid was substantially less affected by rotation than for the constrained case; for the timewise variations of the melted mass and stored energy, the effects of rotation were generally somewhat smaller for the former than for the latter.