A Comment on the measurement of neutrino masses in beta-decay experiments

We discuss the physics potential of future tritium beta-decay experiments having a sensitivity to a neutrino mass ~\sqrt{|\Delta m^{2}_{23}|}~5x10^{-2} eV. The case of three-neutrino mixing is analised. A negative result of such an experiment would imply that the neutrino mass spectrum is of normal hierarchical type. The interpretation of a positive result would depend on the value of the lightest neutrino mass: if the lightest neutrino mass satisfies the inequality min(m_j) << \sqrt{|\Delta m^{2}_{23}|}, it would imply that the neutrino mass spectrum is of the inverted hierarchical type