Volume, excluded historical

Historically, the concept of a hollow cage is rooted to the fifth century B.C. when Democritus postulated the existence of immutable atoms characterized by size, shape, and motion. A motion of atoms requires the existence of a free, unoccupied, or empty space, or a void (nothingness) as a real entity [16]. The concept of the free space (free volume) was exploited 135 years ago by J. D. van der Waals in his PhD thesis [17] (see also Ref. [18] as current reference), as the volume which complements the volume excluded by a molecule... 

Historically, the Zimm theory of A, was developed before the treatment of the excluded volume effect by Flory. 

Actually, the ideal volume of a gas is equal to the difference between the real volume occupied by the gas less the excluded volume of the gas entities. The excluded volume corresponds to the excluded molar volume or covolume, denoted historically by the letter b, and expressed in m mo times the amount of substance, n, in mole. 

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