[Footnote: This chapter is already known through a translation into French by VENTURI. Compare his 'Essai sur les ouvrages physico-mathématiques de L. da Vinci avec des fragments tirés de ses Manuscrits, apportés de l'Italie. Lu a la premiere classe de l'Institut national des Sciences et Arts.' Paris, An V (1797).]
The practice of perspective (72. 73).
72.
In the practice of perspective the same rules apply to light and to the eye.
73.
The object which is opposite to the pupil of the eye is seen by that pupil and that which is opposite to the eye is seen by the pupil.
Refraction of the rays falling upon the eye (74. 75)
74.
The lines sent forth by the image of an object to the eye do not reach the point within the eye in straight lines.
75.