  A new value $b=0.0205\pm0.0017$ fm$^2$ of the slope of the neutron form
factor $G_{En}(q^2)$ at $q^2=0$ compatible with deuteron properties has been
extracted by using a linear relation between $b$ and $A^2_S(1+\eta^2)$ we found
for a class of nonlocal potential models having the experimental values of both
$r_D$ and $Q$. Another {\it model dependent} value $b^{\rm
MHKZ}=0.0206\pm0.0014$ fm$^2$, which is also compatible with deuteron
properties, has been determined by applying "constrained" unitary
transformations to the local MHKZ potential model. The sensitivity of a small
changes in the experimental values used for $r_D$ and $Q$ on the value obtained
for $b$ is also investigated.
