146

The law of the incidence of light.

[figure]

The edges of a window which are illuminated by 2 lights of equal degrees of brightness will not reflect light of equal brightness into the chamber within.

If b is a candle and a c our hemisphere both will illuminate the edges of the window m n, but light b will only illuminate f g and the hemisphere a will light all of d e.

Taken from The Notebooks of Leonardo da Vinci edited by Jean Paul Richter, 1880.

II * IV
Notebooks of Leonoardo da Vinci
III: Six books on Light and Shade.
. . .
Of the various kinds of light.
126,
127
General remarks.
128,
129
On the nature of light.
130,
131
The difference between light and lustre.
132,
133,
134,
135
The relations of luminous to illuminated bodies.
136
Experiments on the relation of light and shadow within a room.
137,
138,
139,
140
Light and shadow with regard to the position of the eye.
141,
142,
143,
144,
145
The law of the incidence of light.
146,
147
Gradations of strength in the shadows.
148,
149
light.
150,
151,
152
On the proportion of light and shade.
153,
154,
155,
156,
157
Definition of derived shadow.
158,
159
Different sorts of derived shadows.
160,
161,
162
On the relation of derived and primary shadow.
163,
164,
165
On the shape of derived shadows.
166
. . .