The discussion revolves around calculating the valency of an element given its equivalent weight of 4 and a vapor density (V.D.) of 59.25. Participants clarify that V.D. refers to vapor density, which is defined as molecular weight divided by two, leading to a molecular weight of 108.50 u. There is confusion regarding the units of vapor density, with suggestions that it should be dimensionless, akin to relative molecular mass. The relationship between equivalent weight and molar weight is emphasized, and the term 'equivalence factor' is suggested as a more accurate descriptor for valency. Understanding these concepts is essential for correctly calculating the valency of the element.