The Descent of Heavy Bodies; a Tumbling Board
Free fall toward the world's centre; oblique weight in two aspects; the mill's roller
Headed 'The descent of the heavy body', the page argues that every natural action follows the shortest path, so a heavy body's free descent is straight toward the centre of the world, the shortest space between it and the lowest point of the universe. A uniform weight descending obliquely divides its gravity into two aspects, proved with a body a b on the slope a b c whose weight is shared along the lines b c and n m, with the question of which aspect bears more deferred to Leonardo's 'book on weights'. In the right margin a board with rotary motion (a / b n / c / m) is caught at successive stages of its tumbling fall, and a closing paragraph returns to the roller (subbio a) of the drawing mill on the facing page, whose turning must span the varying width of the wall.
On this page
Free descent follows the shortest path to the world's centre
Every natural action is done by the shortest way, so the free descent of the heavy body is toward the centre of the world, because that is the shortest space between the moving body and the lowest depth of the universe.
Oblique descent divides the weight into two aspects (a b c / n m)
A uniform heavy body descending obliquely divides its weight into two aspects. Let a b be a body on the oblique a b c; its gravity is shared along the line b c and the line n m. How much more it weighs toward one aspect, and which slope shares the two weights equally, is left to the book on weights.
A board tumbling as it falls (a, b n, c, m)
This board has a revolving motion, and the impetus of that revolution does not let it fall edge-on. In the right margin it is caught at successive positions of its tumbling descent, the sequence marked with repeated letters.
The roller of the drawing mill, continued (subbio a)
The roller a, drawn on the facing page, must turn as far as it can encircle the central line of the cord that pulls the sheet. That line is as long as the width from side to side of the facing wall, which varies irregularly; having no science of it, one must measure at every degree of the wall's height.