Rolls for studies on friction

"Which of these is more easily moving and how much?"

Leonardo is one of the first scholars to study friction (confregazione) systematically, guessing its relevance in the functioning of machines. He makes a distinction between sliding friction and rolling friction. He studies the friction of hinges and examines their behaviour in relation to the nature and shape of materials in contact or by introducing lubricants and rolls. This display shows reproductions of different models of antifriction rolls, each of them marked with a letter.
Manuscript L, sheet 11 v.