Codex Leicester - Overview

Overview

The manuscript does not take the form of a single linear script, but is rather a mixture of Leonardo's observations and theories on astronomy; the properties of water, rocks, and fossils; air, and celestial light. The topics addressed include:

• an explanation of why fossils can be found on mountains. Hundreds of years before plate tectonics became accepted scientific theory, Leonardo believed that mountains had previously formed sea beds, which were gradually lifted until they formed mountains.
• the movement of water. This is the main topic of the Codex. Among other things, Leonardo wrote about the flow of water in rivers, and how it is affected by different obstacles put in its way. From his observations he made recommendations about bridge construction and erosion.
• the luminosity of the moon. Leonardo speculated that the moon's surface is covered by water, which reflects light from the sun. In this model, waves on the water's surface cause the light to be reflected in many directions, explaining why the moon is not as bright as the sun. Leonardo explained that the pale glow on the dark portion of the crescent moon is caused by sunlight reflected from the Earth. Thus, he described the phenomenon of planetshine one hundred years before the German astronomer, Johannes Kepler, proved it.

Physically, the Codex takes the form of 18 sheets of paper, each folded in half and written on both sides, forming the complete 72-page document. At one time the sheets were bound together, but they are now displayed separately. It was handwritten in Italian by Leonardo, using his characteristic mirror writing, and supported by copious drawings and diagrams.