214 FLIPPY. 



rocks and trees are actually moving when for the first time 

 he passes rapidly in a steamer along the banks of a river. 

 He can hardly be persuaded that they do not move. The 

 images of them do really move among each other on the re- 

 tina of his eye, % and he thinks that the objects themselves 

 must move. If you whirl a burning stick in the air before 

 him, he sees a ring of fire, and he thinks there is a real ring 

 of fire there, if he is very young. There is a real ring of 

 the color of fire on the retina of his eye, and he thinks there 

 must be a real ring conforming to it in the air. 



When he grows a little older, he understands that in 

 these simple cases the appearances do not correspond with 

 the reality; but other illusions remain, and are only one 

 after another slowly discovered to be such, as his knowl- 

 edge increases and his reasoning powers become gradually 

 unfolded. I presume there are many readers of this book 

 whom it will be hard to convince of the illusory nature of 

 the deceptive appearances described in the next chapter. 



