REFRACTION OF LIGHT. 51 



power, which matter possesses, of attracting a 

 ray of light. If Mr. Anderson pours some 



Fig. 18. 



water, gently and steadily, into the basin, the 

 water will attract the rays of light downwards, 

 and the piece of silver and the sealing-wax 

 will appear to rise up into the sight of those 

 who were before not high enough to see over 

 the side of the basin to its bottom. [Mr. 

 Anderson here poured water into the basin, 

 and upon the Lecturer asking whether any 

 body could see the silver and sealing-wax he 

 was answered by a general affirmative.] Now, 

 I suppose that everybody can see that they are 

 not at all disturbed, whilst from the way they 

 appear to have risen up, you would imagine 

 the bottom of the basin and the articles in it 

 were two inches thick, although they are only 

 one of our small silver dishes and a piece of 



E 2 



