22 NATURAL THEOLOGY. 



certainty, because it is a matter which experience 

 and observation demonstrate, that the formation 

 of an image at the bottom of the eye is necessary 

 to perfect vision. The image itself can be shown. 

 Whatever aflects the distinctness of the image, af- 

 fects the distinctness of the vision. The formation 

 then of such an image being necessary (no matter 

 how,) to the sense of sight, and to the exercise of 

 that sense, the aparatus by which it is formed is 

 constructed and put together, not only with infi- 

 nitely more art, but upon the self-same principles 

 of art, as in the telescope or the camera-obscura. 

 The perception arising from the image may be 

 laid out of the question ; for the production of the 

 image, these are instruments of the same kind. 

 The end is the same ; the means are the same. 

 The purpose in both is alike ; the contrivance for 

 accomplishing that purpose is in both alike. The 

 lenses of the telescopes, and the humours of the 

 eye, bear a complete resemblance to one another, 

 in their figure, their position, and in their power 

 over the rays of light, viz. in bringing each pencil 

 to a point at the right distance from the lens ; 

 namely, in the eye, at the exact place where the 

 membrane is spread to receive it. How is it pos- 

 sible, under circumstances of such close affinity, 

 and under the operation of equal evidence, to ex- 

 clude contrivance from the one ; yet to acknow- 

 ledge the proof of contrivance having been em- 

 ployed, as the plainest and clearest of all propo* 

 sitions, in the other ? 



