By a process similar to that outlined in the Maxwell–Boltzmann statistics article, it can be seen that: d ln ⁡ ⁡ W = α α d N + β β d E which, using Boltzmann's famous relationship S = k B ln ⁡ ⁡ W becomes a statement of the second law of thermodynamics at constant volume, and it follows that β β = 1 k B T and α α = − − μ μ k B T where S is the entropy, μ μ is the chemical potential, k B is the Boltzmann constant and T is the temperature, so that finally: n i = g i e ( ε ε i − − μ μ ) / k B T − − 1 .