THE EQUIPMENT 



49 



which this interchange takes place would neutralize the Earth's 

 negative charge in a very short time, were there no recharging 

 agent. But radioactivity alone accounts for only a small part 

 of the ions produced in the air. 



The Fore-riggixg 

 Looks very complicated from this angle — it is! 



Recently, penetrating-radiation of "cosmic rays" have been 

 shown to ionize the air. These exceedingly powerful rays can 

 penetrate several feet of lead, and seem to originate entirely out- 

 side our solar system. An apparatus carried on board measures 

 the amount of this energy received by the Earth. However, it 

 does not appear that this accounts for more than another fraction 



