Between 1506 and 1508, as he shuttled between projects in Milan and Florence, Leonardo jotted down his thoughts in a scientific notebook. His intention was to write a treatise on the effects produced by moving water, not only on Earth but also in the sky. Among his notes, tucked into the margin of a page, was a tentative table of contents, with chapter headings that covered many different aspects of water, including its characteristic behavior, its motion in rivers and the sea, the effect of waves along its surface, and the use of dams and canals to control its flow. The 72 pages of Leonardo's notebook contain a wide range of comments. For example, he studied how waves interact when they meet, noticing that two sets of circular ripples run into each other, overlap, then continue on without affecting each other's shape.
Water is of such agility that the motion of any wave . . .
Leonardo understood the difference between the motion of water and the motion of a wave on its surface. Waves breaking on beaches, obstacles diverting the flow of rivers, the shape of air bubbles immersed in water, the generation of whirlpools, devices for traveling under water, along with why the sky is blue and why seashells can be found on mountaintops all attracted his attention. It's like having a magic eye to read Leonardo in his own words. Sample from the Codex Leicester showing the English translation of a portion of the page. It includes reproductions of Leonardo's paintings, detailed commentaries on his writings in the Codex Leicester, and other features, embellished by music of the period.