PROF. ARTHUR LAPWORTH, who is Sir Samuel Hall professor of chemistry at the University of Manchester and director of the chemical laboratories, is retiring in September next. Prof. Lapworth joined the staff of the University of Manchester in 1909 as senior lecturer in chemistry, on vacating his lectureship at Goldsmiths' College, London. He was appointed professor of organic chemistry in 1913, and Sir Samuel Hall professor and director of the laboratories in 1922. He was appointed pro-vice-chancellor in February 1933, and it is a disappointment to the University that his health has not allowed him to exercise the functions of this office during the last few months. During his time at Manchester, Prof. Lapworth has published work in a number of branches of pure organic and physical organic chemistry; he will be remembered for his investigation of the terpenes, his work on certain natural products carried out in association with the Oil and Fats Committee of the Food Investigation Board, and especially for his studies on reaction mechanism and molecular reactivity, which led to the initiation of the now famous ‘electronic’ theory of organic reactions. He has been awarded honorary degrees by the Universities of Birmingham and St. Andrews, and received the Davy Medal of the Royal Society in 1931. His retirement will be a source of deep regret to his many colleagues and students.