PERSPECTIVE.

It is possible to find means by which the eye shall not see remote
objects as much diminished as in natural perspective, which
diminishes them by reason of the convexity of the eye which
necessarily intersects, at its surface, the pyramid of every image
conveyed to the eye at a right angle on its spherical surface. But
by the method I here teach in the margin [9] these pyramids are
intersected at right angles close to the surface of the pupil. The
convex pupil of the eye can take in the whole of our hemisphere,
while this will show only a single star; but where many small stars
transmit their images to the surface of the pupil those stars are
extremely small; here only one star is seen but it will be large.
And so the moon will be seen larger and its spots of a more defined
form [Footnote 20 and fol.: Telescopes were not in use till a century
later. Compare No. 910 and page 136.]. You must place close to the
eye a glass filled with the water of which mention is made in number
4 of Book 113 "On natural substances" [Footnote 23: _libro_ 113.
This is perhaps the number of a book in some library catalogue. But
it may refer, on the other hand, to one of the 120 Books mentioned
in No. 796. l. 84.]; for this water makes objects which are enclosed
in balls of crystalline glass appear free from the glass.

OF THE EYE.

Among the smaller objects presented to the pupil of the eye, that
which is closest to it, will be least appreciable to the eye. And at
the same time, the experiments here made with the power of sight,
show that it is not reduced to speck if the &c. [32][Footnote 32:
Compare with this the passage in Vol. I, No. 52, written about
twenty years earlier.].

Read in the margin.

[34]Those objects are seen largest which come to the eye at the
largest angles.

But the images of the objects conveyed to the pupil of the eye are
distributed to the pupil exactly as they are distributed in the air:
and the proof of this is in what follows; that when we look at the
starry sky, without gazing more fixedly at one star than another,
the sky appears all strewn with stars; and their proportions to the
eye are the same as in the sky and likewise the spaces between them
[61].

[Footnote: 9. 32. _in margine:_ lines 34-61 are, in the original,
written on the margin and above them is the diagram to which
Leonardo seems to refer here.]