IN OPTICS. &3 



: --'^\ ' .-.- * 



with respect to its external condition, seems 



without fault. But whatever is the assistance 

 the motions of the eye afford, in expressing our 

 internal feelings, the whole of it must ulti- 

 mately be referred to the circumstance of ac- 

 curate vision being confined to one point of the 

 retina ; since the intent of those motions is, to 

 bring the pictures of external objects upon the 

 most sensible part of that membrane. Their 

 necessity, therefore, would no longer exist, if 

 the same property were extended, and the ad- 

 vantages we at present enjoy from them, would, 

 consequently, cease. 



