Why Trees Bend, and the Four Accidents of Foliage
Unequal branches bend a tree; luster, light, transparency and shadow on a branching seen by the eye
Here the treatise turns from tree structure to how branches take light. A chapter explains that when a plant's branchings are unequal in thickness it bends to the side opposite the heavier branch, since it must balance between equal weights or a slight wind would topple it. A chapter then names the four 'accidents' of a branching seen by the eye — luster, light, transparency, and shadow — and argues the lit part looks larger than the shaded one, before beginning a scheme of the middle and principal grades of light and shade among the qualities of colour on surfaces. The page is a clear Melzi copy without drawings.
On this page
Why unequal branching bends a tree
When a plant's branchings are unequal in thickness it no longer keeps its straightness but bends to the side opposite the heavier branch. Necessity forces it to balance between equal weights, for otherwise even a small wind blowing along the line of the thicker branch would soon bring it down.
The four accidents of a branching: luster, light, transparency, shadow
The four accidents of the branchings of plants are luster, light, transparency, and shadow. When the eye looks upon a branching, the illuminated part shows as larger than the shadowed, because it contains light, luster, and transparency; setting transparency aside, the illuminated part belongs to the middle grade of the qualities of colour that vary on the surfaces of bodies.