Two typical names of chemicals up to this point in history are "foliated earth of tartar" and "phlogisticated vitriolic acid.” There were hundreds of such names. One goal of the Méthode was to create chemical names based on the chemical composition.

Lavoisier's solution was to use different suffixes to indicate differences in composition. Specifically, the use of "-ous" and "-ic" will be studied.

The IUPAC (International Union of Pure and Applied Chemistry) says "The following systems are in use but not recommended: The system of indicating valence by means of the suffixes -ous and -ic added to the root of the name of the cation may be retained for elements exhibiting not more than two valences."