A detailed study of the supercurrent flow in K3C60 Single crystals is
presented. From de magnetization and ac susceptibility measurements we
obtain the sample dimension over which the superconducting currents f
low. We find that this dimension is identical to the sample size and,
therefore, demonstrates the bulk nature of superconductivity in fuller
enes in an unambiguous way. [S0031-9007(98)07504-8].