  In the neutron-Pb scattering in the MeV. region, existence of the long range
interaction has been known and people have hopefully expected to understand it
as the effect of the electric polarization of the neutron. However the precise
determination of $\alpha_{n}$ in the very low energy region indicates that the
polarizability of the neutron $\alpha_{n}$ is around two order of magnitude
smaller compared to what is expected in the phenomena in the MeV. region. We
need another strong long range potential which decreases faster than $r^{-4}$.
On the other hand, analysis of the low energy proton-proton data revealed the
existence of the strong long range potential whose tail was $V(r) \sim
-C/r^{\alpha}$ with $\alpha=6.08$. The neuton-nucleus scattering is a good
place to see such a force, since the strength $C$ is magnified by factor $A$,
the mass number. Using the long range parameters obtained in p-p, we predict
the characteristic angular dependency of the n-Pb amplitude for fixed energy.
Appearance of a cusp at $\nu=0$, which points upward, in the once subtracted
P-wave amplitude $a_{1}(\nu)/\nu$ is predicted.
