On movers, impetus, and the parts' desire for their whole
Natural-philosophy notes on force and the sphere of fire, with a small winged putto
A densely written leaf sets out Leonardo's natural philosophy of motion: the condensation of air before a flying arrow, the kinds of movers and how they gain their forces, and the doctrine that every part desires to return to its whole. This leads into a cosmological passage on the earth descending to the center of the world and the sphere of fire drawn to that same center, and into a note on the soul's need of the body's organic instruments. A small winged putto is drawn at the center, and a faint curved construction with straight lines appears in the left margin; much further script fills the sheet beyond the two transcribed blocks.
On this page
Movers, impetus and air before the arrow
The note opens on the condensation of the air against an arrow that penetrates it, and on how many kinds of movers there are and how they acquire their forces. It argues that if the perfection of the effect lies in the cause, then the perfection of the impetus lies in the force that generates it.
The earth and the sphere of fire at the center of the world
Every part desires to be within its whole, as the earth does in descending downward; this would not hold if the earth lay outside the center of the world. The sphere of fire is likewise drawn toward that center, its parts fleeing the heavier air, and fire rises within the air for the same reason that air lies beneath water.
Every part rejoins its whole; the soul and its body
Every part has an inclination to rejoin its whole so as to flee its own imperfection. The soul desires to remain with its body, since without the organic instruments of that body it can neither act nor feel.
Faint curved construction in the margin
A faint curved figure crossed by straight ruled lines is drawn low in the left margin, a geometric construction of the sort the leaf's scholarly tags associate with the division of a portion within a rectangle.
Small winged putto
A small standing winged putto is sketched at the center of the sheet, its body lightly modeled, set among the surrounding lines of writing.