The Virginian. [volume] (Lynchburg [Va.]) 1822-1829, 1828-09-11
TIL. HUMAN EYE

No part of ihe human ~ ,trm can be minute
Nv e.am,ned without producing IA every fehee
Ins mind the pfofonndesi reverence fUf ihr De-
ioe ubo oould conifise aud execute, aud put "a
,natien 80 complicated. aud Yet harmonious a
machine. rs thai Of the human name, h"N"g
ven A human body disseci"d, and #its va ious
p1sis anal, z.d aud lrcinred upon was 80
ffemely interested IN Tue peculiar structure al
7 the ~, which, according To the Information
I then received, | shall nnw attempt cohciss'y !"
deseribe.
+ The human eve IS ola spherical form. and
. has t,so ,nembraneous coverings The external
coat which envelnps the eve Is called the scisr0ii
ca II has q projection In fton' tetmed the cor
nen. from its resemblance. when dried, to hue
horn lis 80 oleai aud transparent NAT The
rays Of he ~ ate EASILY Hansu,ired through a.
/ Ibe iofernI membnaeo Is by anaiom"is ter
med the rh0,oid II hHes The cornea, di eclly
psder which there ~ an opening, forming the
pupil through whirh the tight passes INTO the
eve. The puld y sni rounded by culored bni-
der called The IRIS Which 10y the ciren a, arrange
inenf Of lls muscular 6b es, contracts and 80
pands ~ - o. lei INTO the eve nj all times
the samr quantity of hctt. When the eye Is
closed, ne puph eniargps and II u Il suddenly
npeord. before It has iims 10 contract, thu hghi
rnsbrs "a IN sneH quantities ~ 10 pfodu'" -
p intul sensation upon the opne neise. lhi'
is tue reason " Nv 1t Is - unpleasant Rnd nJurI-
Gus 10 the eye 10 wake up ~ the morning ~ n
very light room.
Enclosed wniin those two membrnn"ouS
cnats are THREE transparent substances calico
The napeoue, crYstalline, and vitrcons hun0UF.
fbe aqueous hnmour. called irnm lis fes'In-
bihnoe 10 salcD Is situated directly back OF the
oo,nca, snd ia front nfthe eye ball. The Crys-
n. Al. nj "a Lon
aud Is placed IN the fore part ofthe eve. in'rne.
dIhtely behind the aequeons hnmour-~i' IS per
fectly tram parent. from which circumstance u
ler,se. It's name. fhe yit,eous humpur occu-
PIE. all the posIs,io, par OF the eye between the
fna and cry.iallior lens--like The Crystalline
honou'if' ,ranspgR't bat Ola much softer
sub tance. -
The optic nerve T,AAAf . aOt from the brain in
TO the eye, aud is 6net, spread over the whole
internal surface OF The ehorOId and forms what
Is called the reina On when isr.hceied the in'-
ayes of Objects there 10 be seen and conlrmpla-
ted by The II ind
Tue humuurs of the eye are intended briefly
10 roifact the rays oil light which pa though
the pupil. aud biing thetn To" loeds on The ieli-
ma Rows proctrding from the SIN, 81 any 9TH
~ lnminnry aiitsi iail upunan "hI' q. ihrnce are
reflected 10 thc ry aud passing though the
evsral humours are 50 retiactrd and condens-
ed rs 10 paint Tin lis mlniaiurr upan the relInh
80 that il Is the iu,nge rrnec'cd upon the retna
and not the nhjeel itself, that Wesee.
The human eye Is so perfectly constructed MS
10 form n complete optical Insl'nme NJ. No IN
strnncni. il saul, has ever been nriihciallv
made 10 rritacl the rays OF lght IN 81 perfect
IN nner rs the humonfs Of the eye. Like every
thing else, the hnmau rye is not ai~hNs perfect
" lafmed Sometimes, owing 10 loo gteat CON
vrxitV oftht several humouie, ia" lays ~ hght
nir brought ~ u tncus before reaching the r'tr
IN. To remedy TINS detecl. cnnease glasses
nre used Ivy TINS means the rays dlverge, and
m thrown back upon the retinn. aud these
lo,m a dsliuc' image. In The eyes ri some pr -
sons The humnnrs are too fiat, thereby causing
40 great divergence of the rays, That a yrly
irdistnct image is reflected IN the eve. lo
mnka up the deficiency. CONVEX lens are used
which oondense the feys oil light, aud bIlng
them so near together. iha, q perfect image Is
found aud seem hy the mind on the return.