ANIMALS. 21 



their eyes upon the most brilliant colours, and 

 seem peculiarly desirous of turning them towards 

 the light. Hitherto, however, they only seem to 

 fortify the organ for seeing distinctly ; but they 

 have still many illusions to correct. 



The first great error in vision is, that the eye 

 inverts every object ; and it in reality appears to 

 the child, until the touch has served to undeceive 

 it, turned upside down. A second error in vision 

 is, that every object appears double. The same 

 object forms itself distinctly upon each eye ; and 

 is consequently seen twice. This error, also, can 

 only be corrected by the touch ; and although, 

 in reality, every object we see appears inverted 

 and doubled, yet the judgment, and habit, have 

 so often corrected the sense, that we no longer 

 submit to its imposition, but see every object 

 in its just position, the very instant it appears. 

 Were we, therefore, deprived of feeling, our eyes 

 would not only misrepresent the situation, but 

 also the number of all things round us 



To convince us that we see objects inverted, 

 we have only to observe the manner in which 

 images are represented, coming through a small 

 hole in a darkened room. If such a small hole 

 be made in a dark room, so that no light can 

 come in but through it, all the objects without 

 will be painted on the wall behind, but in an 

 inverted position, their heads downwards. For 

 as all the rays which pass from the different parts 

 of the object without, cannot enter the hole in 

 the same extent which they had in leaving the 

 object, since, if so, they would require the aper- 



