CHAPTER 6 

 Suppose You Were Blind 



In the preceding chapters we have examined waves and 

 echoes to understand better how animals and men have 

 used them to locate objects which are essential for sur- 

 vival. Such studies of natural phenomena often seem use- 

 less to all but a very few people, but so do many scientific 

 explorations. Yet history has clearly shown that men 

 have improved their lot by investigations into the un- 

 known. However insignificant it may have seemed at the 

 time, there is a true inner satisfaction in discovering new 

 relationships and new information to add to our under- 

 standing of the world around us. We often hope that 

 observations and new facts can one day be used to im- 

 prove our environment still further. What could be more 

 beneficial than trying to apply this new-found knowledge 

 to men who cannot see with their eyes? Can we help 

 them to "see" with their ears— to learn the language of 

 echoes? 



Blindness is always a tragedy for human beings be- 

 cause our brains and our whole way of life are built 

 around light and vision. But men's eyes are not their only 

 channels of communication with the rest of the world, 



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