Studies on Hair and the Treatise on Painting (1901) - Page 17

⚠The manuscript is written in Leonardo da Vinci's characteristic mirror-writing (sinistrad writing), which runs from right to left. The text is transcribed here as it would be read normally (left-to-right). Some portions are faded or obscured by the ink of the sketches.

The water that, from a? single source of a fall, divides into various parts—which parts?, being? of? the same substance?, reunite? together? at? the? bottom? of? that? fall? and? create? the? same? motion?, the? same? impetus? term: impetus (impeto). In Leonardo's physics, this refers to the force or momentum an object or fluid possesses while in motion., the? same? increase?, the? same? decrease?, and? the? same? reflected? motion?.

Demonstrate here how the water which, through the due proportions of the heights of various openings, falls? into? the? same? depth? of? water?, divides? itself? into? various? parts?; these? parts? reunite? together? at? the? bottom? and? create? the? same? motion? and? the? same? impetus?.

Here a swirling? of? water? is created, which? is? called? a whirlpool? original: "molinello". Literally 'little mill', Leonardo's term for a vortex or eddy..

Observe that the "fleeces" original: "velli". Leonardo uses this poetic term to describe the textured surface of flowing water, comparing it to the wool or coat of an animal. of the water move in the likeness of hair, which has two motions: one depends on the weight of the fleece, the other on the direction of its curls. Thus, water has its turning revolutions, of which one part depends on the impetus of its course, and the other depends on the incident and reflected motion.