Chap, hi.] 



SIGHT. 



963 



entire, the distance AB will always appear greater than CB. 

 The retinal images of the spaces from A to B and from B to C 

 are equal and the corresponding primary visual sensations are 

 also eqnal, but the mental appreciation of A B is interfered with 

 by the concurrent sensations of the several intervening dots and 

 intervals, and this leads to a mental exaggeration of the interval 

 between A and B. So also, if two equal squares (Fig. 163) be 



A B 



Fig. 163. ■ 



marked, one with horizontal and the other with vertical alter- 

 nate dark and light bands, the former will appear higher, and 

 the latter broader, than it really is. Hence short persons often 

 affect dresses horizontally striped in order to increase their ap- 

 parent height, and very stout persons avoid longitudinal stripes. 

 Again, when a short person is placed side by side with a tall 

 person, the former appears shorter and the latter taller than each 



Fig. 164. 



really is. By reason of somewhat similar psychical processes 

 two perfectly parallel lines or bands, each of which is crossed 

 by slanting parallel short lines (Fig. 164), will appear not 



