A British academic claims to have found the notes made by Leonardo da Vinci where he first recorded his laws of friction.
Ian Hutchings, Professor of Manufacturing Engineering at the University of Cambridge, has identified a page of scribbles in a tiny notebook dating from 1493 which show rows of blocks being pulled by a weight hanging over a pulley, in exactly the same kind of experiment students might do today to demonstrate the laws of friction.
“The sketches and text show Leonardo understood the fundamentals of friction in 1493," said Hutchings. "He knew that the force of friction acting between two sliding surfaces is proportional to the load pressing the surfaces together and that friction is independent of the apparent area of contact between the two surfaces. These are the ‘laws of friction’ that we nowadays usually credit to a French scientist, Guillaume Amontons, working two hundred years later.”
He said it is widely known that Leonardo conducted the first systematic study of friction, which underpins the modern science of “tribology”, but exactly when and how he developed these ideas has been uncertain until now.
Hutchings compiled a detailed chronological study of Leonardo’s work on friction, and has also shown how he continued to apply his knowledge of the subject to wider work on machines over the next two decades.
“Leonardo’s sketches and notes were undoubtedly based on experiments, probably with lubricated contacts,” added Hutchings. “He appreciated that friction depends on the nature of surfaces and the state of lubrication and his use and understanding of the ratios between frictional force and weight was much more nuanced than many have suggested.”
The notebook in question, measuring just 92 mm x 63 mm, is held in the Victoria and Albert Museum in London. In the 1920s, the then Director of the V&A examined the page and was primarily interested in a sketch of an old woman at the top of the page, describing the drawings beneath as “irrelevant notes and diagrams in red chalk”.
Hutchings says they help confirm Leonardo's "position as a remarkable and inspirational pioneer of tribology".
[Leonardo da Vinci's scribble in a notebook could be the first record of the laws of friction. Image: V&A]