.ulrly as my opinions are dia-t.c opposite to those of 



all optical writers. A glass globe filled ^^ 



wth water, and about two inches dia- _;^^x\^ 



meter mav serve those unacquainted -. ./ .^^ 



wfth morb'd dissections. a h, two ^i "^^Z:^-^ 



Tavs of light coming from the uppei ^^^ 



and lower^parts of the candle impingv^ ^^.^ 



on the tvansparent ccu-nea at^ ^^^ ^^» ^^^.,^ ^^^ 



image again tran-i^its ra>s dnei^i . „; \,ified and erect 



^P^^"^ %le r^^Te^att^cotea ralso sends, rays fonnmg 

 image, ine imag^ at „f ♦!,£. rov=: r'-ossinf at ri and e. 



invel-ted images, in consequence "//^^/^/ti^bJ .nd'umtuig into 

 These images take tl^^ ^urya ure of the | ^^e, anci^^^^^^^ ^^^^ 



one inv-ted image,^fo^^ to 



principal refracted tocus aV • ^J , ^ , j i^is eye 



L-eLde his experiments 00^^^^^^^^^ touch tL 



"\-^' 'Id thei-^^s 1 ha e already said, he would have seeu 

 retina; and then as \"* , -[n and not an inverted one, 



an e-ctn^gnihed image of h^^ ^ ^^^^^ ^^ ,,,,. 



«7«-^^lf,,'Lrily urE g how any person could for a moment 

 ration. A^is reauy smpn^ „ r produce vision. 



beUeve that this circle ^^^^^J^i^^^ Co-iightedness they 

 According to the present theoiy of vi.^^^^^^^^ ^^^^ 



say is produced bv the ''^^^l^'^l^^lTZLTlh^ retina in the 

 short-sightedness by an imuge !^oi^^^^"^ /^etore tne 



vitreousWiour-both physical >X' bed ^f ihe eve I wo^uld 

 are supposed to be converged in t^e body ot the eye ^^^^^ 



beg l^ve to put the ^^^^^^Z^:^^. saL man- 

 lens when imbedded »" ^he viteo ^^ ^^^ ^^^^^ 



„er as it would in an . Jr'^^'X^ree basm of water, hold a 

 experiment may show, ^ake a large oas ^^ ^^^^ 



powerful glass lens "^^^^^^^^ ,^ P^^ °"bX^ '^ ^"^^'^ ^^^^ ^"*''' 

 an inverted image on the side of Jhe bas"].^ ^^^ a focus be 



then immei.e the en^relens^^^a^ 



k glass, in proportion to that of wate , s much g.eate^ 



of "the crystalline «^^ ^\P7°?^";\ %5 ays '' It is very 

 humour. 'Mr. Hams m h.s ^P/^,^ ' P;/fi;e Ssures ofthes'e 

 difficult, I thinV, to detennuie accmate^y the me as ^^ ^^^^^^^^ .^ 

 refractions; ^"t, from such experinients as ^^^ 



has been found that the refine ive po ^^^ °^ game with that of 

 vitreous humours are each f ^ h^m m"c tbe same ^^^^^ ^ 



common water, and that ot the ciy-tallinys a iitt ^ 

 that IS the proportion between the sines ot "^cidence anu 

 £ out of Lr Into the cornea or a,^.eo^^^^^^^^^^^ 

 out of the aqueous humour into f^^^ ^ ystaUi^^^^^^ > ^^,, 



