The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1883-08-11
wonders of the Eye.

Youths Home Library.
The eyc-thc organ of sight, more val
liable to us than we can possibly think
is placed where it is needed for use.
The snail in his shell, not wishing to
come out till he is able to see what harm
may befall him, has an eye on each of his
two horns, so that he can thrust those out
and see if there is any danger, before he
exposes his body
Those animals that crawl on the ground,
having no special need of looking down,
but up and on the level, have theirs near
the top of the head; while birds that fly
high, feeding on what they may see and
capture below, not only have the eye lower
on the head, but have it like the telescope,
so moving one part of it that they may sec
objects at a great distance, or very near
Birds that live on fish, in part, being
obliged to 60 under water for them, have
a thin covering that they draw over-like
Il rubber coat-to keep the water out Of
the eye.
The horse, also, has a similar one, to
clean his eye when dust gets into it, rub
bling it so quickly over it that you cannot
easily see the motion.
The fishes in the Mammoth Cave, which
is perfectly dark, have no eyes, simply be-
cause they have no use for them.
The eel, spending his winters in the mud,
often boring his way far under the grassy
marshes, has a horn-like covering for the
eye, through which he can see, as we do
through glass, thus protecting the eye from
being scratched by the gravel.
The spider has from eight to fourteen
eyes, not on the head, but on the forward
part of the back, perhaps that he may the
better see all parts of his web, which he SO
skillfully makes, rather ornamental, won
derfully constructed, each thread of which
is sometimes made Of four thousand smaller
ones, put together like our ropes, the prin-
cipal use of which is to entrap flies and
other small creatures, on which he lives.
The lobster and crab have their eyes at
the end of small tubes, which they can
move in various directions, to make longer
or shorter, as they may find it convenient.
The star-fsh has five eyes at the ends of
the points of the star which give it very
good sight. The body is composed mainly
of jelly, thick at the center, and is fiat like
a pancake when at rest, but is moved
slowly by bringing the edges together, max
ing kind of cup, which moves the body
along as the water is pressed out. If this
singular creature had only two eyes in one
place he could not see all around, as his
jelly body is too thick. When he grows
old this jelly is wasted away, leaving the
star plainly to be seen.
Some of the lower orders of creation are
not satisfied with two eyes only, but have
them by the thousands. What seems to
be an eye, on each side of the head of the
fly, very large, is compound eye having
four thousand facets or eyes, each one of
which is perfect eye, but not movable
like ours. This is like a pepper-box, the
small eyes corresponding with the holes in
the cover The fly has also three in the
front of the head, in all making 5000 eyes
just for one small creature! But, there
are other creatures still richer in sight.
The horse-fy has 5000, the butterfly 3d.
900, the dragon fly $4,000, the beetle So,
000 1t is not strange, therefore, that it
is not easy to approach any of these crea-
lures without being seen, since every one
of these eyes is pointing in different direc-
ton like pistol If these creatures were
compelled to wear gold bowed glasses for
each eye, what an enormous sum of money
it would take to buy the supply!