As we know probability of finding a system in one of its accessible states is proportional to the Boltzmann factor. It is shown that contrary to what is thought at present, in this proportion the energy appearing in the Boltzmann factor is not a variable but it is a constant and the variable is the state accessible for the system having this constant energy. So, what at present is accepted as Boltzmann factor is not real. Deduction of the Maxwell velocity distribution as an instance of the consequences of the real Boltzmann factor, and the first deduction of the relation E=h.nu as an instance of the consequences of the wrong Boltzmann factor are presented. A logical review of some of the fundamental elements of the statistical mechanics, that also contains some new viewpoints, has been necessary. A factor is introduced in a general expression for molar specific heat which plays the role of partition (not equipartition) of energy and giving suitable amounts to it all the practical cases including ones related to ideal gases and crystalline solids are covered.