The motion of water waves and their percussion
Circular waves, shore waves, whirlpools, and the analogy of wave and voice
This crowded sheet is a study of how water waves form and move, illustrated with drawings of ripples, breaking shore waves and small whirlpools. Leonardo distinguishes two principal motions of a wave, notes that a circular wave keeps equal velocity throughout its life yet spreads a wider base as it ages, and reasons about the equal power of colliding waves and how only the parts that meet rebound. Further notes ask why a circular wave broadens with age, why hot water falls in a more compact stream than cold, and compare the reflection of a wave to that of the voice in air (incident versus reflected). The paper is torn along the lower edge, leaving several passages fragmentary.
On this page
Two principal motions of a water wave
Leonardo states that water waves have two principal motions: the first made by water moving on an oblique surface, the second by water struck by a wave of air over water of equal height. The first kind carries two contrary motions within its height, one at its base and another at its crest. Small drawings of ripples accompany the note.
Circular waves collide with equal power
Above two intersecting circles Leonardo asks why a circular wave gains an ever wider base as it grows older. He argues that its motion keeps equal velocity throughout its age, so colliding waves strike with equal power at the point of meeting; only the parts that touch rebound, and because the smaller wave is shallower, it strikes just so much of the larger as its own depth. Water, he adds, is flexible and penetrable by whatever strikes it.
Waves of shores and sea beaches
A central column above a wave drawing is headed with the waves of shores, that is, sea beaches, lettered a o p. The note begins to state that no kind of impetus comes to an end. It links the breaking of waves at the shore to the general study of impetus on the sheet.
The reflection of a wave compared to the voice
A left-hand group of wave figures is labelled incident and reflected. Leonardo compares the reflection of water waves with the voice made in the air, reasoning about how quickly it reaches the ear and rebounds toward its motionless source. The passage is broken by the tear and survives only in fragments.