The impact of water falling on flat ground and on steps
Circular waves from a falling jet, and eddies reflected between staircase steps p, a, b, c
Both folios are headed 'the impact of water falling upon various objects.' On 167v Leonardo describes water dropping in a perpendicular line through a round pipe onto a flat place, which throws up a circular wave that races back toward the point of impact; small fountain-and-basin diagrams accompany the note. On 162r a lettered figure shows water cascading down steps like a staircase, reflecting in eddies between each tread and the riser above, to be studied in water enclosed between two thin plates of glass. A pointed arch with tracery is also sketched in the margin, and further untranscribed text is present.
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Water falling through a round pipe onto a flat place
Water falling in a perpendicular line through a round pipe onto a flat surface makes a circular wave around the point of impact. Within that circle the water is very swift and thin, and finally it strikes the wave it has generated, which seeks to return to the place of impact.
Water falling on a staircase: eddies between the steps
Water falling down steps keeps its simple motion where it clears the step but is reflected between the tread and the riser above where it strikes. Falling from step p a onto step b c with the part a h c, it rebounds from c to c b and from b to a with various eddies, none crossing the straight course d a, c e without being turned back. The true science of these eddies is to be seen in water falling among steps enclosed between two thin plates of white glass.
Pointed arch sketched in the margin
A pointed arch with foliate tracery is drawn in the right margin of the recto. It is not addressed by the transcribed water notes, and its purpose is not stated in the bundle.