Born 1740 in Dresden; died Feb. 26, 1793, in Freiburg. German chemist. Director of mining in Freiburg (from 1780) and chemist at the Meissen Porcelain Factory (from 1786). In Study of the Affinities of Bodies (1777), Wenzel demonstrated that metals dissolve in acids with speeds proportional to the concentrations of the acids (law of mass action). In the same work he expressed the thought, which he considered to be self-evident, that substances combine in fixed proportions, independent of external conditions (law of definite proportions). Wenzel’s works paved the way for the discovery of the law of equivalents.