303 



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 O^'-Oi 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. 



ERRATUM IN PROCEEDINGS OP ROYAL SOCIETY, EDINBURGH, 

 Session 1854-55. 



Page 302, line nine from bottom, after the words " last year," intert by 

 Prof. W. Thomson, 



chamber of the eye, so as to repeat, on difTeront 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 



