CANNIZZARO, STANISLAO (1826-1910), Italian chem ist, was born in Palermo on July 13, 1826. In 1845-46 he acted as assistant to Rafaelle Piria (1815-65), known for his work on salicin, who was then professor of chemistry at Pisa and subse quently occupied the same position at Turin. He took part in the Sicilian Revolution and on the collapse of the insurgents he escaped to Marseille, and reached Paris ;n Oct. 1849. There he worked in the laboratory of M. E. Chevreul, and in conjunction with F. S. Cloez (1817-83) prepared cyanamide by the action of ammonia on cyanogen chloride in ethereal solution (1851). In the same year he was appointed professor of physical chemistry at the National College of Alexandria, where he discovered that aromatic aldehydes are decomposed by alcoholic potash into a mixture of the corresponding acid and alcohol, e.g., benzaldehyde into benzoic acid and benzyl alcohol ("Cannizzaro's reaction"). In the autumn of 1855 he became professor of chemistry at Geneva university, and six years later, after declining professor ships at Pisa and Naples, accepted the chair of inorganic and or ganic chemistry at Palermo. There he spent ten years, studying the aromatic compounds and continuing to work on the amines, until in 1871 he was appointed to the chair of chemistry at Rome university. Apart from his work on organic chemistry, which in cludes also an investigation of santonin, he rendered great service to the philosophy of chemistry when in his memoir Sunto di un torso di Filosofia chinnica (1858) he insisted on the distinction, till then imperfectly realized, between molecular and atomic weights, and showed how the atomic weights of elements contained in volatile compounds 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 as certained from a knowledge of their specific heats. For this achievement, of fundamental importance for the atomic theory in chemistry, he was awarded the Copley medal by the Royal So ciety in 1891. Cannizzaro entered the Italian senate in 1871. He became its vice-president and 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 died in Rome on May 9, 1910.