Giovanni Canestrini’s models of Leonardo da Vinci’s friction experiments

Among the exhibits at the 2016 Leonardo da Vinci exhibition at the Science Museum, London, was one that purported to illustrate Leonardo’s experiments on friction. The models involved were the work of Giovanni Canestrini (1893–1975) who contributed to the 1939 and 1953 Leonardo exhibitions in Milan. This article discusses the original sources and history of these models, in the light of recent research into Leonardo’s work on friction. It concludes that, while being relevant to Leonardo’s study of mechanics, these models seriously misrepresent his experimental investigations of friction.