  In nonspherical nuclei at $J = J_c + 0$ the relationship between the angular
momentum and angular velocity immediately after backbending is the same as in
the limiting case $J - J_c\to\infty$. This indicates that there is a unique
type of cancellation of the deviations from a rigid-body moment of inertia in
the upper phase $J>J_c$. An integral relationship is found which expresses this
cancellation quantitatively. This formula permits $J_c$ to be calculated for
the rotational bands of the even-even nuclei studied and the results are in
agreement with those obtained by other methods of locating the Curie point. For
the ground state band of W$^{170}$ the cancellation of the reciprocals of the
true and rigid-body moments of inertia can be verified directly. The condition
for the stability of the rotation of a nonspherical nucleus is analyzed in the
Appendix in close connection with the problem of a reasonable definition of the
concept of a variable moment of inertia.
