My last communication dealt with the question of what is an atom. The answer was a proposal to define the atom as the terminus of a special sort of analysis, the atomistic-structural. This form of analysis was presented as a special way of treating a “material” system or situation. A formula was suggested which expressed matter or the material as the product of structure and atomicity, or M = SA. No limitation was placed on the factoring of M into other products, but this particular product was designated as the structural-atomistic analysis. The factors, S and A, constitute a conjugate pair, so chosen that each member of the pair is meaningless without the other. Atomicity, thus, is not a matter of size or of some sort of ultimateness, but corresponds to some level of being in empirical situations which also reveals structure.