Persistence of velocity and the theory of second order GAS reactions

R. H. Fowler has stated that if, in second order gas reactions, it is supposed that reaction occurs whenever two reactant molecules collide with sufficient velocity, then the deviation from the Maxwell distribution law which would result is so great that this law cannot be used in calculating the rate of the reaction. It is shown that this view is sometimes in error, and that in a mixture of molecules of nearly equal mass reacting in this way the molecular velocities do not diverge appreciably from the predictions of the Maxwell law.