280 OUR PHYSICAL WORLD 



communication to take over a very large part of the work now 

 being handled by the commercial wire telephone and telegraph 

 systems. Especially will this superseding of the wire systems 

 by the radio systems occur where long-distance transmission is 

 concerned. Radio communication is not subject to the serious 

 limitations in expense of right-of-ways for pole lines and cables, 

 the cost of maintaining large central stations, and the inter- 

 ference of communication because of the effects of such devastat- 

 ing elements as storms, floods, and fire. 



