300 NATURAL THEOLOGY. 



XVII. 



THE EYE COMPARED WITH OPTICAL INSTRUMENTS. 



We have elsewhere expressed our surprise that 

 the structure of an animal body should so seldom 

 be taken as a model. In the history of inventions, 

 it appears quite extraordinary that the telescope 

 and the microscope should be modern, when, as it 

 should seem, the fine transparent convexity of the 

 eye might have given rise to imitation, as soon as 

 man learned to give shape to natural or artificial 

 glass. It reminds us of the observation of Locke, 

 in speaking of a discovery, that it proved the 

 world to be of no great antiquity. Yet we must 

 estimate the invention of the telescope and micro- 

 scope as by far the most important in their conse- 

 quences of either ancient or modern discoveries. 

 The first opens to us an unlimitted expanse, not 

 only of new worlds, but systems of worlds, and new 

 laws evinced in the forces which propel and at- 

 tract these ; since in the heavenly bodies we find 

 no material contact, nor pressure, nor impulse, nor 

 transfer of power — nor effect of heat, nor expan- 

 sion of gases — nothing, in short, which can be 

 illustrated by mechanism. By the microscope, 

 we contemplate the minute structure of animals 

 and things but for its aid invisible: the balance of 



