It has thus been rigorously proved that whatever may have been the initial distribution of kinetic energy, in the course of time it must necessarily approach the form found by Maxwell. […] This [proof] actually gains much in significance because of its applicability on the theory of multi-atomic gas molecules. There too, one can prove for a certain quantity \(E\) that, because of the molecular motion, this quantity can only decrease or in the limiting case remain constant. Thus, one may prove that, because of the atomic movement in systems consisting of arbitrarily many material points, there always exists a quantity which, due to these atomic movements, cannot increase, and this quantity agrees, up to a constant factor, exactly with the value that I found in [Boltzmann 1871c] for the well-known integral \(\int dQ/T\).