Jean Servais Stas
Stas, Jean Servais
Born Sept. 20 (according to some sources, Aug. 21), 1813, in Leuven; died Dec. 13, 1891, in Brussels. Belgian chemist. Member of the Belgian Academy of Sciences (1841).
Stas graduated from the university in Leuven in 1835 and began working with J. Dumas in 1837. He was a professor of chemistry at the Military Academy in Brussels in the years 1840–65, and until 1872 he was an official at the Mint. His research, which dealt mainly with determining the atomic weights of chemical elements, corroborated the law of definite proportions. Although he proposed in 1860 that oxygen (atomic weight, 16.000) be used as a standard of reference for setting up atomic-weight scales, his suggestion was not adopted until 1906. (The carbon scale was adopted for atomic weights in 1961.) The values obtained by Stas for atomic weights remained unequaled in precision until the end of the 19th century.