£2 
APPLICATION OF THE ARGUMENT. 
through sand and gravel, the roughest and harshest sub¬ 
stances, there is placed before the eye, and at some dis¬ 
tance from it, a transparent, horny, convex case or cover¬ 
ing, which, without obstructing the sight, defends the or¬ 
gan. To such an animal, could anything be more wanted, 
or more useful? 
Thus, in comparing the eyes of different kinds of ani¬ 
mals, we see, in their resemblances and distinctions, one 
general plan la>d down, and that plan varied with the vary¬ 
ing exigencies to which it is to be applied. 
There is one property, however, common, I believe, to 
all eyes, at least to all which have been examined,* namely, 
that the optic nerve enters the bottom of the eye, not in the 
centre or middle, but a little on one side; not in the point 
where the axis of the eye meets the retina, but between 
that point and the nose. The difference which this makes 
is, that no part of an object is unperceived by both eyes at 
the same time. 
In considering vision as achieved by the means of an 
image formed at the bottom of the eye, we can never re¬ 
flect without wonder upon the smallness, yet correctness, 
of the picture, the subtilty of the touch, the fineness of the 
lines. A landscape of five or six square leagues is brought 
into a space of half an inch diameter; the multitude of 
objects which it contains, are all preserved; are all discrim¬ 
inated in their magnitudes, positions, figures, colors. The 
prospect from Hampstead-hill is compressed into the com¬ 
pass of a sixpence, yet circumstantially represented. A 
stage-coach, travelling at its ordinary speed for half an 
hour, passes, in the eye, only over one-twelfth of an inch, 
yet is this change of place in the image distinctly per¬ 
ceived throughout its whole progress; for it is only by 
means of that perception that the motion of the coach it¬ 
self is made sensible to the eye. If anything can abate 
our admiration of the smallness of the visual tablet compar¬ 
ed with the extent of vision, it is a reflection, which the 
view of nature leads us, every hour, to make, viz. that in 
the hands of the Creator, great and little are nothing. 
Sturmius held, that the examination of the eye was 
a cure for atheism. Besides that conformity to optical 
principles which its internal constitution displays, and 
which alone amounts to a manifestation of intelligence hav¬ 
ing been exerted in the structure; besides this, which forms, 
* The eye of the seal or sea-calf, I understand, is an exception.—Mem 
Acad. Paris, 1701, p. 123. 
