The Transition from Alchemical to Modern Chemical Symbolism: from Bergman and Guiton de Morveau to Hassenfratz and Adet, Higgins, Richter, Dalton, and Berzelius

The alchemical concepts of chemical symbolism, nomenclature, and affinity underwent fundamental changes between the 1770s and the 1820s, roughly simultaneously with the Chemical Revolution (ca. 1772–89), i. e. the replacement of the phlogiston theory with Lavoisier's New Chemistry. Using the old, alchemical symbols, Bergman devised a system of formulas to describe virtually all known inorganic chemistry, and he influenced Guiton de Morveau's Mémoire sur les Dénominations Chimiques, and the subsequent Méthode de nomenclature. Hassenfratz and Adet devised a new artificial sign language which, however, was too complicated and unintuitive to gain widespread acceptance. Bergman refined the concept of affinity, but his belief in phlogiston rapidly made the system obsolete. Wenzel realized that the dissolution of metals in acids is not just a question of affinity but rather of concentration, and he and Berthollet separately formulated early versions of the Law of Mass Action thereby making attempts to quantify affinity redundant. Richter formulated a principle that became known as the Law of Equivalent Proportions, describing acid‐base reactions and double decompositions of salts, but continuing to use Bergman‐style alchemical formulas. Only John Dalton's atomic theory with little globules denoting atoms and their combination into molecules made a definite break with the alchemical symbols. The alchemical symbols for metals, acids, bases and salts were still in everyday use in much of the 18th century. The modern notation, which we use today, is due to Berzelius, but the transition was long and arduous and took place between ca. 1775 and 1820 roughly simultaneously with but distinct from the Chemical Revolution. The notations of Bergman and Dalton (pictured) were stages of the process, which had to deal with the thorny questions of affinity, stoichiometry, the forces that bind atoms together in molecules, and the constitution of molecules.