The Notebooks of Leonardo Da Vinci by Leonardo Da Vinci Read Free Book Online

spot where
these pyramids are received into the eye. Therefore, if you extend
the lines from the edges of each body as they converge you will
bring them to a single point, and necessarily the said lines must
form a pyramid.]
    [Perspective is nothing more than a rational demonstration applied
to the consideration of how objects in front of the eye transmit
their image to it, by means of a pyramid of lines. The Pyramid is
the name I apply to the lines which, starting from the surface and
edges of each object, converge from a distance and meet in a single
point.]
    [Perspective is a rational demonstration, by which we may
practically and clearly understand how objects transmit their own
image, by lines forming a Pyramid (centred) in the eye.]
    Perspective is a rational demonstration by which experience confirms
that every object sends its image to the eye by a pyramid of lines;
and bodies of equal size will result in a pyramid of larger or
smaller size, according to the difference in their distance, one
from the other. By a pyramid of lines I mean those which start from
the surface and edges of bodies, and, converging from a distance
meet in a single point. A point is said to be that which [having no
dimensions] cannot be divided, and this point placed in the eye
receives all the points of the cone.
    [Footnote: 50. 1-5. Compare with this the Proem. No. 21. The
paragraphs placed in brackets: lines 1-9, 10-14, and 17—20, are
evidently mere sketches and, as such, were cancelled by the writer;
but they serve as a commentary on the final paragraph, lines 22-29.]
    51.
IN WHAT WAY THE EYE SEES OBJECTS PLACED IN FRONT OF IT.
    The perception of the object depends on the direction of the eye.
    Supposing that the ball figured above is the ball of the eye and let
the small portion of the ball which is cut off by the line s t be
the pupil and all the objects mirrored on the centre of the face of
the eye, by means of the pupil, pass on at once and enter the pupil,
passing through the crystalline humour, which does not interfere in
the pupil with the things seen by means of the light. And the pupil
having received the objects, by means of the light, immediately
refers them and transmits them to the intellect by the line a b .
And you must know that the pupil transmits nothing perfectly to the
intellect or common sense excepting when the objects presented to it
by means of light, reach it by the line a b; as, for instance, by
the line b c . For although the lines m n and f g may be seen
by the pupil they are not perfectly taken in, because they do not
coincide with the line a b . And the proof is this: If the eye,
shown above, wants to count the letters placed in front, the eye
will be obliged to turn from letter to letter, because it cannot
discern them unless they lie in the line a b; as, for instance, in
the line a c . All visible objects reach the eye by the lines of a
pyramid, and the point of the pyramid is the apex and centre of it,
in the centre of the pupil, as figured above.
    [Footnote: 51. In this problem the eye is conceived of as fixed and
immovable; this is plain from line 11.]
    Experimental proof of the existence of the pyramid of sight (52-55).
    52.
    Perspective is a rational demonstration, confirmed by experience,
that all objects transmit their image to the eye by a pyramid of
lines.
    By a pyramid of lines I understand those lines which start from the
edges of the surface of bodies, and converging from a distance, meet
in a single point; and this point, in the present instance, I will
show to be situated in the eye which is the universal judge of all
objects. By a point I mean that which cannot be divided into parts;
therefore this point, which is situated in the eye, being
indivisible, no body is seen by the eye, that is not larger than
this point. This being the case it is inevitable that the lines
which come from the object to the point must form a pyramid. And if
any man seeks to prove that the sense of sight does not