Reflected Light and the Shadow Under Building Eaves
Opaque body d, the dark body a c, and the darkening shadow cast beneath cornices
The page opens by finishing a rule that a surface partakes of the colour of its object, illustrated by a diagram in which the opaque body d, luminous body a n, dark body a c, and lit plane c d together produce light, shadow, and reflected light. A vivid three-dimensional pen sketch of a projecting roof or cornice, with the sun above casting rays, illustrates the next proposition: the shadow beneath the eaves of buildings, cast by the sun, grows darker at every degree of the sun's height. A final line begins a note on things seen indoors, lit by a high window.
On this page
Opaque body d between a luminous and a dark body
Let d be the opaque body, a n the luminous body, a c a body of dark colour, and c d the plane lit by the hemisphere a f m n. By the foregoing, r is more lit than o, o than s, and s than t; the parts turned toward the dark body a c behave alike, and so those turned toward the lit place c d — whence arise light, shadow, and reflected light.
Shadow beneath the eaves of buildings
The shadow that remains beneath the projections of the coverings (eaves) of buildings, cast by the sun, acquires darkness at every degree of the sun's height. A perspective sketch shows the sun above a projecting roof, its rays defining the deepening shade beneath the overhang.
Things seen indoors by a high window
A concluding line begins the next proposition: a thing seen within dwellings illuminated by a particular, high light from some window shows a strong difference between its lights and shadows, especially if the room is large or dark.