Affinity tables came into use in the eighteenth century. They provided a diagrammatic picture of the main chemical reactions, displaying the natural resemblances—in other words, the affinities—between two substances. The different configurations of the Tables reflected the variety of chemical concepts and systems.
The first Table was compiled in 1718 by the French chemist Étienne-François Geoffroy, who entitled it Table des differents Rapports observés entre differentes substances. It served as the model for the Tabula affinitatum inter differentes substantias at the Museo Galileo of Florence. The only difference is that the Florentine Table has an extra column.
The chemical substances, arranged in seventeen vertical columns, are shown here with traditional alchemical symbols. At the top of each column are the basic substances used by the chemist. The position of the substances underneath indicates the degree of affinity with the basic substance. A substance immediately below the basic substance has a closer affinity with it than the substance in the third cell, and so on.
For example, let us combine copper, placed in the third cell, with lead, the basic substance of the eleventh column. If we add silver—a substance listed in the second cell of the same vertical column—the lead will separate from the copper and blend with the silver, a substance with which it possesses greater affinity.
Last update 23/feb/2008