This paper demonstrates the equivalence between two equations for correlating liquid kinematic viscosities: the Heric and McAllister equations. For ternary and multicomponent mixtures, the only difference is in the ternary interaction term. If this term is constant, both equations correlate the viscosity data identically. This approach can prove the equivalence of the Nissan and Grunberg equation and the Frenkel equation to correlate the dynamic viscosity of liquid mixtures. Examples are included for binary and ternary mixtures.