can be deduced from the molecular weights of those compounds, and how the atomic weights of elements of whose compounds the vapour densities are unknown can be determined from a knowledge of their specific heats. For these achievements, of fundamental importance to atomic theory, he was awarded the Copley Medal by the Royal Society in 1891. In 1871, Cannizzaro's scientific eminence secured him admission to the Italian senate, of which he was vice-president, and as a member of the Council of Public Instruction and in other ways he rendered important services to the cause of scientific education in Italy. He is best known for his contribution to the then-existing debate over atoms, molecules, and atomic weights. He championed Amedeo Avogadro's notion that equal volumes of gas at the same pressure and temperature held equal numbers of molecules or atoms, and the notion that equal volumes of gas could be used to calculate atomic weights. In doing so, Cannizzaro provided a new understanding of chemistry. Works Sunto di un corso di filosofia chimica, Genova, 1858 Scritti intorno alla teoria molecolare ed atomica ed alla notazione chimica, "Lo Statuto" (Palermo), 1896, . Scritti vari e lettere inedite nel centenario della nascita, Roma, 1926 See also Cannizzaro reaction References External links Sketch of a course of chemical philosophy by Cannizzaro (1858) – Edinburgh: Alembic Club Reprint No. 18 (1911). by Thomas Edward Thorpe in Essays in Historical Chemistry, London: Macmillan, pages 500 – 513 (also Nature, 6 May 1897). George B. Kauffman, (1996). Review of Lettere a Stanislao Cannizzaro 1868–1872; Stanislao Cannizzaro: Scritti di Storia Politica e Chimica; Corrispondenza Varia, a set of Cannizzaro's papers 1826 births 1910 deaths Scientists from Palermo Italian chemists Recipients of the Copley Medal Members of the Senate of the Kingdom of Italy Faraday Lecturers Foreign Members of the Royal Society Members of the Royal Academy of Belgium Corresponding members of the Saint Petersburg Academy of Sciences Burials at San Domenico, Palermo