SUPPOSE YOU WERE BLIND 



recorder. This experiment demonstrated the effectiveness 

 of our built-in suppressor mechanism which renders 

 echoes far less audible because our ears are temporarily 

 insensitive immediately after a loud outgoing sound. A 

 multitude of echoes are clearly audible on reversed play- 

 back when they precede a sharp chck or pistol shot, but 

 are quite unnoticed when they follow the louder sound 

 as they do in ordinary life. Is this the major reason why 

 blind men fail to learn as much from echoes as they 

 theoretically should? And if so, could not some device 

 be developed to overcome this difficulty? No one knows 

 the answers to these questions, and they are good ex- 

 amples of the truism that no branch of science is com- 

 plete or finished. Perhaps some reader may have the 

 ideas and the opportunity to make further advances to- 

 ward a real solution of the bUnd man's problems of 

 orientation. Just because some men have failed so far to 

 find such a solution, others should not be discouraged 

 from new attempts, especially when the potential gains 

 to human welfare are so great. 



145 



