Studies of friction, ball bearings and point contact
An antifriction device, spheres touching 'at a point,' and a four-wheel bearing
This sheet is one of Leonardo's studies of friction and antifriction bearings. A device weighing 20 pounds prompts the question whether weight and force joined together equal the load on pole a. Three spheres a; b; c, each 'touching at a point,' are asked which makes the greater contact with its support, and five circles model a pole turning within four wheels, where the line n a alone makes the wheel turn. A square inscribed in a circle and columns of arithmetic complete the page.
On this page
Antifriction device: weight versus force
An antifriction mechanism marked 'libbre 20 - 5 a 5' carries both a weight and a force, the weight acting perpendicular and the force across it. Leonardo asks whether weight and force joined together equal the load on pole a, or whether the force is precisely the excess over the natural weight.
Spheres touching 'at a point' (a; b; c)
A ball bearing is inscribed 'Touch me at a point.' Of three spheres a; b; c Leonardo asks whether each touches at a single point, and which of a, b or c makes the greater contact with its support.
A pole turning on four wheels (a-m-b-n)
Five circles model a pole resting within four wheels set level and equally near their points of contact. Leonardo reasons that such a pole turns almost as freely as on a flat plane: m b rouses pole b, a m pushes the pole toward a, and the line n a alone makes the wheel turn.
Square inscribed in a circle
A square is inscribed within a circle, annotated 00-21. It sits among the mechanical figures as a geometric aside.
Columns of figures
Several columns of numbers and additions are worked at the margins of the sheet. They accompany the mechanical and geometric studies without a stated purpose.