Centre of gravity of a suspended weight and the balance
Statics of an obliquely hung rod and lever equality, amid quadrature figures
Two mechanical notes analyse gravity and the balance. A suspended heavy body, Leonardo states, lies wholly along the central line of its suspender, while a rod set obliquely has two gravities — a natural one, perpendicular to the centre of the world, and an accidental one — a distinction that holds only where the mathematical centre is not the centre of rotation. A lettered balance figure (c a, b, d) shows that a lever and its counter-lever fall into one line only when they are in equality. Squares, lunes and small circles for squaring figures, a rectangle marked 100, and the numbers 310–310–334–351 also appear, and further faint annotations remain untranscribed.
On this page
The suspended weight and the oblique rod
The suspended heavy body is said to lie wholly, in the whole and in every part, along the central line of its suspender. A rod set obliquely has two gravities: a natural one perpendicular to the centre of the world and an accidental one that is oblique, a difference arising where the mathematical centre is not the centre of the revolving body.
Lever and counter-lever in equality (c a, b, d)
A lettered balance figure carries the marks c a, b and d. Leonardo notes that when the lever and the potential counter-lever stand in the position of equality they form one and the same line, which never happens while the small hangers keep the real angle a d b.
Quadrature figures: squares, lunes and circles
Along the upper band the sheet carries several small squaring diagrams: a square crossed by its diagonals, half-moon lunes set within rectangles, and small inscribed circles. These are the recurring circle-and-lune figures that the Codex Atlanticus classes under geometry.
Numbers 100 and 310–334–351
A small rectangle near the top is marked 100, and a further line records the figures 310, 310, 334 and 351. They read as measures or quantities set beside the geometric and mechanical diagrams rather than as a running calculation.