46 Observations on the Vision of the Retina. 



tina. If we approach a concave or convex mirror in a certain 

 direction, our image is seen inverted on the margin of the glass, 

 but on going nearer to the centre, the figure is right again. 



One thing, however, is row brought to a decision. If some- 

 thing else sees the retina, then that something else must convey 

 the impression of outward objects to the mind or sensory. My 

 opinion is, that as the whole apparatus of the eye is merely to 

 modulate and convey light, there is no occasion for any inter- 

 mediate agent to form a regular image to assist the mind in 

 its conception or apprehension of outward forms and qualities. 

 All that the mind can ever know of outward objects and their 

 qualities is from the rays of light themselves, which by their 

 density — meaning by density their various lengths, the dif- 

 ferent lengths answering to different colours — act upon the 

 nerves of vision far away from the eye itself. 



Independently of the certainty, which the above facts bring 

 to the mind, that the retina is not the seat of vision, I have 

 elsewhere proved that the vitreous humour is not the place 

 where images are formed, for by a reference to page 306 of a 

 work, entitled " Neighbourhood," it will there be found that 

 we can see part of the interior of our own eye. At the time 

 that was written I fully believed that the retina was the seat 

 of vision, and I made that belief the base of my deductions 

 from that curious phasnomenon ; I could not perceive then 

 that any other part of the eye was adapted to the purpose of 

 conveying the appearance of bodies to the mind, for the use of 

 the lens was fully understood; and as to the choroides, that part 

 could not for one moment be supposed the seat of vision, 

 as the office of all dark colouring matter is simply to decom- 

 pose light. 



Mary Griffiths. 



Observations by the Editor. 



Although some of the conclusions in the preceding paper, 

 and especially those about the seat of vision, are not correct, 

 yet as we believe, on the authority of direct experiment, that 

 most of the phenomena described may be distinctly seen, we 

 have thought it right to lay the experiment before our readers, 

 and establish Mrs. Griffiths's claim as the first observer of a 

 fact so curious. 



In repeating the experiments under different modifications, 

 we have observed several curious facts, which will be commu- 

 nicated in a subsequent paper. D. B. 



