The British scientist Augustus Matthiessen (1831-1870) is widely known for his investigations on the influence of temperature on the electric conductivity of metals and alloys. However, his contributions to other areas of science throughout his career are not widely acknowledged. His research on the electrolytic decomposition of metallic salts resulted in the isolation of pure alkali and alkaline earth metals--including calcium, magnesium, strontium, and lithium--as well as the identification of some of their properties. His studies on the definitive composition and formulas of a group of alkaloids and the products resulting from their decomposition contributed to the establishment and definition of a general and consistent system of nomenclature for organic compounds in the 19th century.