22 NATURAL THEOLOGY. 



besides the known laws of mechanism taking place ; where- 

 as, in the automaton, for the comparatively few motions ol 

 which it is capable, we trace the mechanism throughout. 

 But, up to the limit, the reasoning is as clear and certain in 

 the one case as in the other. In the example before us it 

 is a matter of certainty, because it is a matter which expe 

 rience and observation demonstrate, that the formation of ai; 

 image at the bottom of the eye is necessary to perfect vision 

 The image itself can be shown. Whatever affects the dis- 

 tinctness of the image, affects 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 apparatus by which it is formed is construct- 

 ed and put together not only with infinitely more art, but 

 upon the selfsame 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 accomplisliing that purpose is 

 in both alike. The lenses of the telescopes and the humors 

 of the eye bear a complete resemblance to one another, in 

 their figure, their position, and in their power over the rays 

 of light, namely, in bringing each pencil to a point at the 

 right distance from the lens ; namely, in the eye, at the ex- 

 act place where the membrane is spread to receive it. How 

 is it possible, under circumstances of such close affinity, and 

 under the operation of equal evidence, to exclude contriv- 

 ance from the one, yet to acknowledge the proof of contriv- 

 ance having been employed, as the plainest and clearest ni 

 all propositions, in the other ? 



The resemblance between the two cases is still more ac- 

 curate, and obtains in more points than we have yet repre- 

 sented, or than we are, on the first view of the subject, aware 

 of. In dioptric telescopes there is an imperfection of this 

 nature. Pencils of light, in passing through glass lenses 



