79

The intersection of the rays.

[figure]

OF THE CENTRAL LINE OF THE EYE.

Only one line of the image, of all those that reach the visual virtue, has no intersection; and this has no sensible dimensions because it is a mathematical line which originates from a mathematical point, which has no dimensions.

According to my adversary, necessity requires that the central line of every image that enters by small and narrow openings into a dark chamber shall be turned upside down, together with the images of the bodies that surround it.

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

78 * 80
I * III
Notebooks of Leonoardo da Vinci
II: Linear Perspective.
. . .
59,
60,
61,
62,
63,
64
Proof by experiment.
65,
66
General conclusions.
67
That the contrary is impossible.
68
A parallel case.
69
The function of the eye as explained by the camera obscura.
70,
71
The practice of perspective.
72,
73
Refraction of the rays falling upon the eye.
74,
75
The inversion of the images.
76
The intersection of the rays.
77,
78,
79,
80,
81,
82
Demomstration of perspective by means of a vertical glass plane.
83,
84,
85
The angle of sight varies with the distance.
86,
87,
88
Opposite pyramids in juxtaposition.
89
On simple and complex perspective.
90
The proper distance of objects from the eye.
91,
92
eye.
93,
94,
95,
96,
97,
98
The apparent size of objects defined by calculation.
99
. . .