PHYSIOLOGICAL PARADOXES. 



effect of perspective is to bring apparently 

 nearer to the spectator at E the points G and H, 

 at which the clouds really do come down to 

 horizon-level, and so to give a sharper slope 

 to the appearance of spreading upwards and 

 outwards. The appearance of spreading out- 

 wards, however, is appearance and nothing 

 more. 



3. False Levels. 



The view of a scene often produces a wrong 

 impression as to which parts of it are higher 

 and which are lower. 



Cyclists, who are very sensitive to fine 

 differences of level, not seldom find that a road 

 which presented the appearance of a fairly stiff 

 rise in front of them is in reality level, or even 

 slightly down-hill. More frequently, but less 

 agreeably, it happens that what looked in front 

 like a coming occasion for easy driving or 

 possibly free-wheeling, is actually more or less 

 of a rise. 



Such errors are usually made by the judg- 

 ment rather than by the eyes. We misinterpret 

 the appearances caused by a level beyond a 

 rise, or a dip beyond a level, a gradual widen- 

 ing or narrowing, a passage into or out of shade, 

 an increase or decrease in the size of trees 

 adjoining the road, a 'difference between the 

 actual gradient of the road and its general 

 direction up or down a valley or a mountain. 



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