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tion of the resisting medium, Professor Smyth had instituted, 

 during the last summer, a series of observations on stars in the 

 neighbourhood of the sun. Atmospheric difficulties had, however, 

 prevented much being done ; and in the whole history of the ob- 

 servatory, but one group of observations available for the purpose 

 in view had been found. This, on being subjected to special cal- 

 culation, has given two results, both confirmatory, and indicating an 

 amount of solar refraction of 0''04 in right ascension, at a distance of 

 12 minutes of time from the sun. 



2. On the Extent to which the Theory of Vision requires us 

 to regard the Eye as a Camera Obscura. By Dr George 

 Wilson. 



The object of this communication was to combat the current 

 theory of vision, as exercised by vertebrate animals, in so far as it 

 teaches that the light which reaches the retina from without, there- 

 after passes through that membrane, and is absorbed by the pigment 

 of the choroid behind it. 



The author first enumerated the arguments adduced in favour of 

 this view, such as, 



1. The difficulty in assigning any other use for the choroid than 

 that of absorbing the light which falls upon it. 



2. The advantages known to result in artificial camerse obscurse 

 from the internal darkening of their walls. 



3. The confusion which must attend visual perception, if the 

 rays by which objects are seen are reflected several times across the 

 chamber of the eye, so as to repeat, on different points of the retina, 

 the image of a solitary object. 



4. The painful and imperfect vision known to characterize the 

 human albino. 



The author then proceeded to state that a mass of evidence, daily 

 accumulating, had established, beyond question, the certainty that 

 light is reflected from the anterior layers of the retina and from the 

 choroid, and so abundantly, that oculists take daily advantage of the 

 fact, to examine, by means of this light, the deeper internal struc- 

 tures of the eye. 



This organ, accordingly, cannot be regarded otherwise than in a 

 limited sense as a camera obscura, and the arguments in favour of 



