  Dilatations by means of a constant factor can be seen in a double way: as a
simple change of units length or as a conformal mapping of the starting
spacetime into a ``stretched'' one with the same units length. The numerical
value of the black hole entropy depends on the interpretations made for the
stretched manifold. Further, we study the possibility to choose an unusual
``mass dependent'' normalization for the timelike Killing vector for a Kerr
black hole with and without a cosmic string.
