As long as there is an interval of play between the wheel and the axle, there is a rotary action. It is the interval of play that keeps the wheel and axle in touch. And the gap or interval is "where the action is." This fact has gained special attention from the new physics; and it is in the very opening of "The Nature of the Chemical Bond" that Linus Pauling explains there are "no connections" in matter. The development of the theory of quantum mechanics has also introduced into chemical theory a new concept, that of resonance ... and it is our resonant interval ...