Ralph Louis Wain died on 14 December 2000, at the age of 89 years. Just a few weeks before his death he had kept an audience enraptured by his enthusiastic presentation of chemical ideas during a two-hour lecture. Louis applied his chemical acumen to the solution of agricultural problems, believing the advancement of agricultural practice was highly dependent on developments in chemistry. He was interested particularly in how subtle changes in the structures of chemicals could influence their plant-growth-regulatory properties, and he discovered and actively promoted a group of selective herbicides, some of which are still used today in commercial practice. Many would regard him as Britain's most outstanding agricultural chemist of the twentieth century. He received numerous honours and prizes, but two gave him especial pleasure, perhaps because of their unusual citations. These were the Actonian Prize of the Royal Institution of Great Britain, awarded only every seventh year, for outstanding scientific work ‘which illustrated the wisdom and beneficence of the Almighty’ (previous winners had included Edison, Marconi, Marie Curie and Fleming), and the John Scott (USA) International Award for ‘research for the benefit, welfare and happiness of mankind’. Wain was ever conscious of the need to protect and increase the harvests of food crops for the peoples of poorer, developing countries, and he was a major player in scientists' successes in increasing food crop production.
Louis took every opportunity to convey his ideas and enthusiasm to fascinated audiences, whether they were schoolchildren or learned scientists, at home or abroad. He listed travel as one of his hobbies. Did this passion derive from the many invitations he received to lecture abroad? Whatever the answer, he gained great satisfaction from this role; and his audiences were most appreciative of his lucid lecturing style, and often the puckish humour with which his ideas were presented.