  The equivalence of thermodynamic results in the canonical and the
microcanonical ensembles has been questioned in some calculations for spin
models with long-range interactions. We show that these claims of inequivalence
are related to an inadequate definition of the independent (density) variables
in the microcanonical ensemble. We illustrate this point with the example of a
simple spin-1 ideal paramagnet, and then revisit the original calculations of
Barr\'e, Mukamel, and Ruffo, for a mean-field spin-1 Blume-Capel model. If the
microcanonical ensemble is defined in terms of adequate density variables, we
show that there is no disagreement with the calculations in the usual canonical
ensemble (with fixed thermodynamic field variables).
