  The heat capacity (C) of a mesoscopic nonsuperconducting fermion system
treated as a canonical ensemble of independent particles is studied in a wide
range of particle numbers and temperatures which vary from values close to zero
up to the Fermi energy. The temperature evolution of C is naturally divided
into four stages. On the first one the heat capacity exponentially increases
with temperature and at a resonance temperature reaches either a local maximum
or an irregularity in its growth. This resonance temperature being measured can
give information concerning the level spacings in the immediate proximity of
the Fermi energy. On the second stage the progressive suppression of the level
density oscillations takes place. During this stage oscillations of C v.s.
particle number N can be distinctly observed. These oscillations give the
N-variations of the temperature averaged level density. The growth of C on the
third stage of the evolution is governed by the T-linear law if the particle
number is large enough (N>1000). It is found that the Sommerfeld factor in the
linear law for such small systems shows more complicated N-dependence as
compared with large systems where C is strictly proportional to N. For
temperatures tending to the Fermi energy the deviations from the T-linearity
are evident and at T larger than the Fermi energy (the fourth stage of the
evolution) any system attains to the classic Boltzmann-Maxwell limit
irrespective of the particle
