14 APPLICATION OF THE ARGUMENT. 



umination of the instrument goes, there is precisely the 

 same proof that the eye was made for vision, as there is 

 that the telescope was made for assisting it. They are 

 made upon the same principles; both bemgj adjusted to the 

 laws by which the transmission and retraction of rays of 

 light are regulated. I speak not of the origin of the laws 

 themselves; but, such laws being fixed, the construction, 

 in both cases, is adapted to them. For instance ; these 

 laws require, in order to produce the same effect, that the 

 rays of light, in passing from water into the eye, should be 

 refracted by a more convex surface than when they passed 

 out of air into the eye. Accordingly we find, that the eye 

 of a fish, in that part of it called the crystdliine lens, is much 

 rounder than the eye of terrestrial animals. [Plate II. fig. 1.] 

 What plainer manifestation of design c^n there be than this 

 difference ? What could a mathematical instrument maker 

 have done more, to show his knowledge of his prmciple, 

 his application of that knowledge, his suiting of his means 

 to his end ; I will not say to display the compass or excel- 

 lency of his skill and art, for in these all comparison is 

 indecorous, but to testify counsel, choice, or consideration, 

 purpose ? 



To some it may appear a difference sufficient to destroy 

 all similitude between the eye and the telescope, that the 

 one is a perceiving organ, the other an unperceiving instru- 

 ment. The fact is, that they are both instruments. And, 

 lis to the mechanism, at least as to mecimnism being em- 

 ployed, and even as to the kind of it, this circumstance va- 

 ries not the analogy at all. For observe, what the constitu- 

 tion of the eye is. [Plate II. fig. '2, 3, 4.] It is necessary, in 

 order to produce distinct vision, that an image or picture of 

 the object be formed at the bottom of the eye. Whence this 

 necessity arises, or how the picture is connected with the 

 sensation, or contributes to it, it may be difficult, nay we 

 will confess, if you please, impossible for us to search out. 

 But the present question is not concerned in the inquiry. It 

 may be true, that in this, and in other instances, we trace 

 mechanical contrivance a certain way; and that then we 

 come to something which is not mechanical, or which is in- 

 scrutable. But this affects not the certainty of our inves- 

 tigation, as far as we have gone. The difference between 

 an animal and an automatic statue, consists in this, — that, 

 in the animal, we trace the mechanism to a certain point, 

 and then we are stopped ; either the mechanism becoming 

 foo subtile for our discernment, or something else b^sido 



