158 



EXPERIMENTS AND INVESTIGATIONS 



light on the side a (fig. 21), the fringes // vanish, but not 

 the external fringes c. This at once proves there is no inter- 

 ference in forming the external ones. Lastly. I 

 may observe, that the law of disposition and 

 polarization in some sort, though with modifica- 

 tion, affects the internal fringes as well as the 

 external. 



It is a curious fact connected with polarization 

 by inflexion, and which indeed is only to be ac- 

 counted for by that affection of light, that nothing else pre- 

 vents the rays from circulating round bodies exposed to them, 

 at least bodies of moderate diameter. If the successive 

 particles of the surface inflected, one particle acting after the 

 other, the rays must necessarily come round to the very point 

 of the first flexion. We should thus see a candle placed at 

 A (fig. 22) when the eye was placed at B, because the rays 

 would be inflected all round ; and even 

 in parts of the earth where the sea 

 is smooth, nothing but the small curva- 

 ture of the surface could prevent us 

 from seeing the .sun many hours after 



^ ni S ht had * Q g bv P lacin S the C 3" e 



close to the ground. This, however, 



in bodies of a small diameter, must 

 inevitably happen. The polarization of the rays alone pre- 

 vents it, by making it impossible they should be more than 

 once inflected on their side which was next the bending body, 

 therefore they go on straight on to C. But for polarization 

 they must move round the body. 



7. It must not be lightly supposed, that because such 

 inquiries as we have been engaged in are on phenomena of a 

 minute description and relate to veiy small distances, then- 

 fore they are unimportant. Their results lead to the con- 

 stitution of light, and its motion, and its action, and the 

 relations between light and all bodies. I purposely abstain 

 from pursuing the principles which I have ventured to 

 explain into their consequences, and reserve for another 



