On Motion in General; the Wind on Mountain Slopes
A syllabus of questions on motion, impetus and rebound, with a note and sketch of wind rising over ridges
The upper text sets out a program of study 'on motion in general,' listing questions about the cause and nature of motion, impetus, percussion, rebound and the curving of straight motion, and citing Aristotle's Physics (books three and seven), Albert, Thomas and On the Heavens and the World as authorities. The lower text and a faint pen sketch of flowing lines describe how wind striking mountain slopes rises to the summit, presses into the opposing straight wind and spreads down the far slope, so that people below cannot tell an eddying wind from a straight one. The whole page is in mirror-writing with the wind study illustrated by curved flow lines.
On this page
A program of questions on motion and impetus
Leonardo asks what is the cause of motion, what motion is in itself, what is most apt to move, what impetus is and where it is created, what percussion and rebound are, and what causes a straight motion to curve. He cites Aristotle's Physics, Albert, Thomas and On the Heavens and the World as sources.
Wind rising and spreading over a mountain slope
Wind striking the shores or flanks of mountains rises to the summit, presses into the course of the opposing straight wind, and then spreads out grazing the far slope. Because the eddies run below, above and sideways, those living beneath the hills cannot tell an eddying wind from a straight one.
Sketch of wind currents over a ridge
A group of light, curving pen lines runs across the lower half of the sheet, sweeping up and over a raised profile. The drawing illustrates the accompanying note on how wind flows up and across a mountain slope.