Lesson xxxvn.] THE EYE. 283 



at a considerable distance j and a horse, which 

 may be in the middle of a plain, not moving, 

 and in an attitude similar, for instance, to that of 

 a sheep, may in the dusk appear in every sense like 

 a sheep. 



If, therefore, we are benighted in a strange place, 

 where no judgment of distance can be formed, we 

 are every moment liable to deceptions of vision. 

 Hence originate niost of the dreadful stories of 

 spectres, and of those wonderful, hideous and 

 gigantic figures, which many persons speak of hav- 

 ing seen. Though it is commonly asserted, that 

 such figures exist solely in the imagination ; yet it 

 is highly probable, that they might appear to the 

 Eye in every respect as described. This remark 

 will be allowed to have the greater force, when it 

 is considered, that if the size of an object be in 

 grekt measure estimated by the angle which it 

 forms in the Eye, it is magnified according to its 

 propinquity : of course, if it seemed at first to the 

 spectator (who is equally incapable of distinguish- 

 ing what he sees, and of judging at what distance 

 it is,) a few feet high, when at the distance of thirty 

 or forty yards from him : it must look to him, when, 

 he is within a. few feet of it, of a size stupendously 

 increased. At this he will naturally be terrified, 

 unless he touch and 'hus distinguish the seemingly 

 enormous object j for in* the instant he has an 

 actual perception of what it is, the enormity will 

 diminish, and the object will appear in its real 

 state: if, on the other hand, he be afraid to ap- 

 proach it, and flee from the spot with precipita- 



lion, 



