  Small metallic grains which satisfy the conditions of the universal
Hamiltonian are considered. It is shown that for such grains the effects of the
interactions in the spin channel and in the Cooper channel on their spin
magnetization are well separated, thus allowing the determination of the
interaction parameters within this model. In particular, the existence of
pairing correlations in small grains and the sign of the interaction in the
Cooper channel can be uniquely determined.
