NATURAL THEOLOGY. 



29 



capac'ty of change. It is as though an optician, 

 when he had a nearer object to view, should rec- 

 tify his instrument by putting in another glass, at 

 the same time drawing out also his tube to a differ- 

 ent length.^ 



Observe a new-born child first lifting up its eye- 

 lids. What does the opening of the curtain dis- 

 cover ? The anterior part of two pellucid globes, 

 which, when they come to be examined, are found 

 to be constructed upon strict optical principles; 

 the self-same principles upon which we ourselves 



9 This is a subject over M^hich there is still great obscurity, and 

 on which adverse experiments and opinions are recorded. How- 

 ever difficult it may be to account for the mode of adjustment, yet 

 the property is not denied, and therefore the argument in the text 

 remains. That there is something in the sensibility of the nerve, 

 and in the power of attention, there seems no doubt. Birds of 

 prey, it has been noticed, possess a power of vision of which we 

 can hardly form a conception. Where it is the object to snare the 

 falcon, a pigeon is tied, in an exposed situation, with a cord so at- 

 tached that a person concealed can flutter the bird, or make it ex- 

 tend its wings ; and although no bird of prey be visible in the 

 whole sky, presently the hawk will be seen descending to pounce 

 upon the pigeon. The endowment of the bird's eye must be dif- 

 ferent from ours, else the bird of prey could not see the most mi- 

 nute object when hovering at a great height; nor, in sweeping 

 down upon his quarry, could he strike it with precision. Nothing 

 of the nature of mere mechanical provision can account for the 

 possession of this superior power. One instance of the power of 

 adjustment which the eye has under the influence of the will, 

 seems to be this. Let a person who cannot read distinctly, or at 

 all, without spectacles, at a given distance, look at a word through 

 a very small aperture, and he will see what he before could not 

 without spectacles. This can hardly be explained by the removal 

 of the lateral Ught, or by inflexion. 



3* 



