  The thermodynamic properties such as the specific heat are uniquely
determined by the second moments of the energy distribution for a given
ensemble averaging. However for small particle numbers the results depend on
the ensemble chosen. We calculated the higher moments of the distributions of
some observables for both the canonical and the microcanonical ensemble of the
same van der Waals clusters. The differences of the resulting thermodynamic
observables for the two ensembles are calculated in terms of the higher
moments. We demonstrate how for increasing particle number these terms decrease
to vanish for bulk material. For the calculation of the specific heat within
the microcanonical ensemble we give a new method based on an analysis of
histograms.
